This PDF file contains the front matter associated with SPIE Proceedings Volume 6684, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

The GSICS is a new program within the World Meteorological Organization (WMO) Space Programme and is coordinated by NOAA/NESDIS/STAR. The overarching objective of GSICS is to improve the calibration and characterization of space-based measurements through satellite intercalibration of the international satellite observing system. The GSICS program currently includes participation from the United States (NOAA, NASA, NIST), Europe (CNES/France, EUMETSAT), China (CMA), Japan (JMA) and Korea (KMA). These agencies have agreed to take steps to ensure better comparability of satellite measurements made by different instruments and to tie these measurements to absolute standards. The direct benefit of improved satellite observations will be improved weather and climate assessments and predictions. Satellite intercalibration is vital for reducing measurement uncertainty and to optimally integrate data from different observing systems to support the GEO nine societal benefits. The GSICS activities are currently focused on the intercalibration of operational satellites from United States, Europe, China, Japan and Korea.

The Microwave Sounding Unit (MSU) on board the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites were designed to measure the atmospheric temperature from the surface to the lower stratosphere under all weather conditions, excluding precipitation. Although the instrumental design and calibration were made primarily for monitoring the atmospheric weather processes, the MSU observations have been extensively used for detecting climate trend. However, calibration errors have been a major uncertainty in climate trend detections. In order for the MSU data to be of high quality for climate trend and variability research, we have recently recalibrated the MSU satellites NOAA 10, 11, 12, and 14 using simultaneous nadir overpass (SNO) method. The calibration results in a well-merged 20-year radiance dataset for the MSU channels 2, 3, and 4. Limb-correction is applied to adjust the incident angles of the footprints. The limbcorrected radiances are further binned into 2.50 longitude by 2.50 latitude grids to generate deep-layer temperature datasets for the mid-troposphere (T2), tropopause (T3), and lower-stratosphere (T4). The global ocean averaged trends for the recalibrated T2, T3, and T4 are respectively 0.234±0.071 K/decade, 0.079±0.085 K/decade, and -0.414±0.287 K/decade for the 20-year time period from 1987 to 2006. Both the recalibrated radiance and deep-layer temperature datasets are freely available through the NESDIS/STAR website http://www.orbit.nesdis.noaa.gov/smcd/emb/mscat/mscatmain.htm htm.

The current generation of the Geostationary Operations Environmental Satellite (GOES) platform employs a total of 5 sensors to monitor and record atmospheric conditions used in predictions of upcoming weather events. Included in this package is a 5-band imager that, from the 36,000-km geosynchronous orbit inhabited by GOES platform, enables multiple fixed full-disc surface images of the earth during the course of a 24-hour day. There is currently no on-board radiometric calibration for the visible bands of the imager and radiometric calibration relies on vicarious approaches. The Remote Sensing Group (RSG) at the University of Arizona uses a vicarious approach that relies on ground-based measurements to determine the radiometric calibration for multiple sun-synchronous and airborne visible and near-infrared sensors. The current work extends the approach to the GOES I-M series of sensor. The paper presents the methods and results of the reflectance-based method applied to the 1-km visible channel of GOES-11using large North American high-desert test sites. Modifications to the RSG's methods to take into account the location of the test sites at large zenith angles within the full-disk GOES image. The work provides an opportunity to evaluate uncertainties of the spectral BRF of the test sites at large view angles and resulting importance to the accurate radiometric calibration of a sensor. In addition, the impact of increased path length caused by the large view angle is evaluated with an emphasis on the increased effect of the atmospheric characterization.

The Korean Geostationary satellite (COMS) to fly in year 2009 will carry a meteorological sensor from which visible channel measurements will be available. We developed a method utilizing satellite-derived BRDFs for the solar channel calibration over the bright desert area. The 6S model has been incorporated to account for directional effects of the surface using MODIS-derived BRDF parameters within the spectral interval in interest. Simulated radiances over the desert targets were compared with MODIS and SeaWiFS measured spectral radiances in order to examine the feasibility of the developed calibration algorithm. It was shown that simulated 16-day averaged radiances are in good agreement with the satellite-measured radiances within about ±5% uncertainty range for the year 2005, suggesting that the developed algorithm can be used for calibrating the COMS visible channel within about 5% uncertainty level.

Successful transition into a (robust and vibrant) enterprise realization of the Global Earth Observing System of Systems (GEOSS), and the Integrated Earth Observations System (IEOS) as the US component, spans a domain that includes: (1) the transition from research to operations across the "valleys of death and lost opportunities"; (2) the linkage of observations, analysis and modeling systems through data assimilation and the global forecast system; (3) stakeholders aligned along an "axis of good" that includes NSF, NASA, NOAA and its Cooperative Institutes, and end users who deliver socioeconomic benefits. An often-overlooked, yet critical, element of this enterprise is the bidirectional nature of the interfaces; specifically, the transition from operations to research. It is this return path that empowers the iterative and continuously improving nature of the enterprise. This paper evaluates three "best of breed" systems that are designed to exploit and enable the operations-to-research transition: the University of Wisconsin- Madison's Man computer Interactive Data Access System (McIDAS) V, the NOAA/National Weather Service's Advanced Weather Interactive Processing System (AWIPS) II, and the Air Force's Joint Environmental Toolkit (JET). From these, lessons learned and common attributes are identified. These provide a set of demonstrated and success-oriented best practices that future environmental systems may consider for incorporation into their objectives and requirements.

The Remote Sensing Group at the University of Arizona has been active in the vicarious calibration of numerous sensors through the use of ground-based test sites. Recent efforts have included work to develop cross-calibration information between these sensors using the results from the reflectance-based approach. The current work extends the cross-calibration to the AVHRR series of sensors, specifically NOAA-17, and NOAA-18. The results include work done based on data collected by ground-based personnel nearly coincident with the sensor overpasses. The available number of calibrations for the AVHRR series is increased through a set of ground-based radiometers that are deployed without the need for on-site personnel and have been operating for more than three years at Railroad Valley Playa. The spectral, spatial, and temporal characteristics of the 1-km² large-footprint site at Railroad Valley are well understood. It is therefore well suited for the radiometric calibration of AVHRR, which has a nadir-viewing footprint of 1.1 x 1.1 km. The at-sensor radiance is predicted via a radiative transfer code using atmospheric data from a fully-automated solar radiometer. The results for AVHRR show that errors are currently larger for the automated data sets, but results indicate that the AVHRR sensors studied in this work are consistent with the Aqua and Terra MODIS sensors to within the uncertainties of each sensor.

Analyses of a 4.5 year SNO (Simultaneous Nadir Overpass) time series between AVHRR on NOAA-16 and -17 suggest that the AVHRR observations based on operational vicarious calibration have become very consistent since mid 2004. This study also suggests that the SNO method has reached a high level of relative accuracy (~1.5%, 1 sigma) for both the 0.63 and 0.84 μm bands, which outperforms many other vicarious methods for satellite radiometer calibration. Meanwhile, for AVHRR and MODIS, a 3.5 year SNO time series suggests that the SNO method has achieved a 0.9% relative accuracy (1 sigma) for the 0.63 μm band, while the relative accuracy for the 0.84 um band is on the order of +/- 5% and significantly affected by the spectral response differences between AVHRR and MODIS. Although the AVHRR observations from NOAA-16 and -17 agree well, they significantly disagree with MODIS observations according to the SNO time series. A 9% difference was found for the 0.63 μm band (estimated uncertainty of 0.9%, 1 sigma), and the difference is even larger if the spectral response differences are taken into account. Similar bias for the 0.84 μm band is also found with a larger uncertainty due to major differences in the spectral response functions between MODIS and AVHRR. It is expected that further studies with Hyperion observations at the SNOs would help us estimate the biases and uncertainty due to spectral differences between AVHRR and MODIS. It is expected that in the near future, the calibration of the AVHRR type of instruments can be made consistent through rigorous cross-calibration using the SNO method. These efforts will contribute to the generation of fundamental climate data records (FCDRs) from the nearly 30 years of AVHRR data for a variety of geophysical products including aerosol, vegetation, and surface albedo, in support of global climate change detection studies.

The NOAA AVHRR program has given the remote sensing community over 25 years of imager radiances to retrieve global cloud, vegetation, and aerosol properties. This dataset can be used for long-term climate research if the AVHRR instrument is well calibrated. Unfortunately, the AVHRR instrument does not have onboard visible calibration and does degrade over time. Vicarious post-launch calibration is necessary to obtain cloud properties that are not biased over time. The recent AVHRR/3 instrument has a dual gain in the visible channels in order to achieve greater radiance resolution in the clear-sky. This has made vicarious calibration of the AVHRR/3 more difficult to unravel. Reference satellite radiances from well-calibrated instruments, usually equipped with solar diffusers, such as MODIS, have been used to successfully vicariously calibrate other visible instruments. Transfer of calibration from one satellite to another using co-angled, collocated, coincident radiances has been well validated. Terra or Aqua MODIS and AVHRR comparisons can only be performed over the poles during summer. However, geostationary satellites offer a transfer medium that captures both parts of the dual gain. This AVHRR/3 calibration strategy uses Meteosat-8 radiances (calibrated with MODIS) simultaneously to determine the dual gains using 50km regions. The dual gain coefficients will be compared with the nominal coefficients. Results will be shown for all visible channels for NOAA-17.

The Global Space-based Inter-Calibration System (GSICS) is an international collaboration to build an operational system for the inter-calibration of a variety of meteorological satellite instruments. GSICS is a critical thread that links individual observation systems for integration into the Global Earth Observation System of Systems (GEOSS). This paper reviews the four categories of satellite instrument inter-calibration, reports on recent progress and current status of GSICS, and presents preliminary results from a prototype system.

The EUMETSAT Polar System (EPS) is the European contribution to the joint European/US operational polar satellite system (Initial Joint Polar System (IJPS)). It serves the mid-morning (AM) orbit, whereas the US part continues to serve the afternoon (PM) orbit. The satellites of this new polar system are the Metop (Meteorological operational Satellite) satellites, jointly developed with ESA. They deliver high-resolution sounding and also high-resolution imagery in global coverage. Three Metop spacecraft are foreseen for a sun synchronous orbit in the 9:30 AM equator crossing (descending node). They provide polar data from October 2006 onwards, when the first Metop satellite was launched. The EPS programme is planned to cover 14 years of operation. This paper gives an overview on the EPS mission, the products and services provided to users, and shows first results obtained from Metop-A during the commissioning and initial operations phase. All programme components support operational meteorology and climate monitoring, and hence provide a contribution to Global Earth System Monitoring.

IASI was successfully launched on MetOP A on 19 October 2006. After the in-orbit commissioning, the performances of IASI were evaluated during the Cal/Val of level 1. Key parameters of instrument and on ground processing have been fixed for optimal performance and best quality data delivery. The first spectra and images of level 1 products show all the potential of IASI data for expected applications. Some illustrations are given here with maps of pseudo channels sensitive to trace gases, atmospheric profiles or maps of surface temperature qualitatively compared to maps from models. Level 2 processing to get these parameters has been implemented at Eumetsat and some products are currently under validation. The quality of IASI data paves the way to additional very promising products. A thorough analysis of cloud free spectra has been performed to extract the small signature of minor species like CFCs and HNO₃. Nevertheless, the main limitation of IASI data remains clouds. It is showed here with the cluster analysis of AVHRR data registered in the IASI pixels and delivered as level 1 products that only a few cloud free pixels can used for full retrieval. A method making use of the cluster information has been developed. It permits to strongly increase the statistics where clear column profiles or columns above clouds can be retrieved. This scheme will be applied to the retrieval of the CO₂ where large data set are needed to extract information from the spectra.

The Infrared Atmospheric Sounding Interferometer (IASI) is a key element of the payload embarqued on METOP series of European meteorological polar-orbit satellites. IASI will provide very accurate data about the atmosphere, land and oceans for application to weather predictions and climate studies. IASI measurements will allow to derive temperature and humidity profiles with a vertical resolution of one kilometer and an average accuracy of one Kelvin and 10 % respectively. The IASI measurement technique is based on passive IR remote sensing using a precisely calibrated Fourier Transform Spectrometer operating in the 3.7 - 15.5 μm region and an associated infrared imager operating in the 10.3-12.5 μm region. The optical configuration of the sounder is based on a Michelson interferometer. Interferograms are processed by the onboard digital processing subsystem which performs the inverse Fourier Transform and the radiometric calibration. The integrated infrared imager allows the coregistration of the IASI soundings with AVHRR imager onboard METOP. The first METOP satellite was successfully launched on 19th of October 2006. This paper summarizes the IASI instrument radiometric, spectral and geometric performance as measured in orbit during the Calibration and Validation Phase. Instrument noise, spectral and radiometric calibration stability and spatial pointing accuracy are discussed as well as the performance of the Level 1 Processing chain.

In this paper the simulated space-based high spectral resolution infrared radiances with different cloud top heights and effective cloud fractions are used to demonstrate the measurement sensitivity and atmospheric profile retrieval performance. The simulated cloudy retrieval of atmospheric temperature and moisture derived from the statistical eigenvector regression algorithm are analyzed with and without the cloud top height classification. Collocated cloudy AIRS (the Atmospheric InfraRed Sounder) and the associated clear MODIS (the Moderate Resolution Imaging Spectroradiomete) infrared observations within the AIRS field of view (FOV) are also used to demonstrate the profile retrieval improvement below the cloud layer. The results show that the knowledge of cloud height is critical to sounding retrieval performance. In addition this paper has demonstrated that the use of collocated clear MODIS multi-spectral imager data along with the AIRS high spectral resolution infrared radiances can greatly improve the single FOV cloudy retrieval even under opaque cloudy condition.

Three-fold restriction technique is used to determine the standard deviation of the error in the total-ozone content obtained from the three independent data resources such as ground-based station data, TOMS (Total Ozone Mapping Spectrophotometer) and GOME (The Global Ozone Monitoring Experiment) in 1995-2004. The results show that, in general, the accuracy of TOMS V8 data is the best and that of ground-based observations is the worst. Since the ground-based observations can be classified into 3 types according to the equipment principles such as Filter, Brewer and Dobson, the standard deviation of the errors for the 3 types of ground data are also calculated with the 3-fold restriction technique and it has been found that the Filter has the largest error, the Brewer is the second, and the Dobson is the least. The data quality at Shiangher Dobson Station of China is better than either TOMS or GOME. The data quality at Waliguan Brewer Station of China is better than TOMS, but worse than GOME. The error in TOMS V8 is evidently less than in TOMS V7 because of the algorithm amelioration of TOMS V8 over TOMS V7.

An improved atmospheric profile retrieval system for the current Geostationary Operational Environmental Satellite (GOES) Sounder data process has been developed. This algorithm can also be applied to process Advanced Baseline Imager (ABI) on the next generation GOES-R to continue the current GOES class Sounder legacy products. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) data from the Meteosat Second Generation (MSG) satellite is employed as proxy to test and evaluate the algorithm for ABI legacy product. Since there is only a few sounding spectral bands in SEVIRI, a first guess from forecast is needed in legacy profile retrieval. The results show that if a set of temperature/humidity profiles from weather forecast is applied as first guess, the accuracy of temperature/humidity profiles can be achieved with that from the current GOES Sounder. Considering that there is only one temperaturesensitive spectral band in SEVIRI, temperature information is limited; however, the improvement on humidity profile retrieval over forecast is noticeable because there are two water vapor absorption spectral bands in SEVIRI. The results of total precitable water (TPW) and lift index (LI) from combined SEVIRI and forecast are presented as well.

Surface emissivity plays an important role in the retrievals of surface and atmospheric parameters from satellite IR measurements. In this research, a physical algorithm has been developed to retrieve hyperspectral IR emissivity spectrum simultaneously with temperature and moisture profiles as well as surface skin temperature. To retrieve the hyperspectral IR emissivity, the emissivity spectrum is represented by the eigenvectors, derived from the laboratory measured hyperspectral emissivity database, in the retrieval process. Simulations are carried out with profiles over different land surface properties and results show that simultaneous retrieval of emissivity spectrum can improve the surface skin temperature as well as temperature and moisture profiles retrievals, particularly for the boundary layer moisture. The algorithm has further been applied to the Atmospheric Infrared Sounder (AIRS) radiance measurements, which covers a diversity of land surface types. The retrievals have then been compared with the ECMWF analyses and radiosonde observations, and shown a very good agreement.

The AIRS Science Team Version 5.0 retrieval algorithm became operational at the Goddard DAAC in July 2007 generating near real-time products from analysis of AIRS/AMSU sounding data. This algorithm contains many significant theoretical advances over the AIRS Science Team Version 4.0 retrieval algorithm used previously. Three very significant developments of Version 5 are: 1) the development and implementation of an improved Radiative Transfer Algorithm (RTA) which allows for accurate treatment of non-Local Thermodynamic Equilibrium (non-LTE) effects on shortwave sounding channels; 2) the development of methodology to obtain very accurate case by case product error estimates which are in turn used for quality control; and 3) development of an accurate AIRS only cloud clearing and retrieval system. These theoretical improvements taken together enabled a new methodology to be developed which further improves soundings in partially cloudy conditions, without the need for microwave observations in the cloud clearing step as has been done previously. In this methodology, longwave CO₂ channel observations in the spectral region 700 cm^-1 to 750 cm^-1 are used exclusively for cloud clearing purposes, while shortwave CO₂ channels in the spectral region 2195 cm^-1 to 2395 cm^-1 are used for temperature sounding purposes. The new methodology for improved error estimates and their use in quality control is described briefly and results are shown indicative of their accuracy. Results are also shown of forecast impact experiments assimilating AIRS Version 5.0 retrieval products in the Goddard GEOS 5 Data Assimilation System using different quality control thresholds.

Algorithm has been developed for retrieving atmospheric temperature and moisture profiles from hyperspectral infrared (IR) sounder radiances under both clear and cloudy skies. Focus has been on handling surface emissivity and clouds in IR only sounding retrieval.

The application of infrared hyper-spectral sounder data to climate research requires the global analysis of multi-decadal time series of various atmosphere, surface or cloud related parameters. The data used in this analysis has to meet stringent global and scene independent absolute accuracy and stability requirements, it also has to be spatially and radiometrically unbiased, manageable in size and self-contained. Self-contained means that the data set contains not only a globally unbiased sample of the state of the Earth Climate system as seen in the infrared, it has to contain enough data to contrast clear with average (cloudy) data and to allow an independent assessment of the radiometric and spectral accuracy and stability of the data. We illustrate this with data from the Atmospheric Infrared Sounder (AIRS) and Infrared Atmospheric Sounder Interferometer (IASI) data. AIRS and IASI were designed with fairly similar functional requirements. AIRS was launched on the EOS Aqua spacecraft in May 2002 into a 705 km polar sun-synchronous orbit with accurately maintained 1:30 PM ascending node. Essentially un-interrupted data are available since September 2002. Since October 2006 IASI is in a 9:30 AM polar orbit at 815 km altitude on the MetOp2 satellite, with data available since May 2007.

Determination of aerosol optical depth from satellite remote sensing measurements is extremely complex due to the large variability of aerosol optical properties. Significant simplification occurs when measurements are taken over water since the ocean reflection signal can be taken as negligible in the NIR. Unfortunately, over land, most of the signal can be attributed to ground reflectance. While conventional approaches look for "dark" pixels in an image to isolate aerosols, these pixels are subjected to increased noise. In this paper, we focus on the feasibility of the MODIS sensor to determine aerosol optical depth. In particular, an intercomparison between MODIS and CIMEL shows a significant trend for MODIS to overestimate optical depth. We show that this may be explained through an inaccurate assumption on the correlation between the VIS and NIR surface albedos. In particular, we show through an analysis of hyperspectral high resolution Hyperion data that the correlation coefficient assumption underestimates ground albedo resulting in an overestimate of the VIS optical depth. Using a series of coincident measurements between aeronet and MODIS, we estimate a more accurate angle dependant albedo and use it to determine aerosol optical depth. The results show significantly less overbias. Our efforts to reduce space resolution to 1.5km are also discussed.

Using daily rainfall measurements from 740 stations across China and European Centre for Medium-Range Weather Forecasts (ECMWF) upper air reanalysis daily data (1958-2001), we give out climatically characters of East Asian summer monsoon's (EASM) movement with the definition of the EASM's front, finding out that the transfer of the rain belt over East China is consistent with the advance and retreat of the EASM. By the EOF (empirical orthogonal function) analysis of the gridded EASM's index (average for the 28th-45th pentad) from 1958 to 2001 in area (105°E-150°E,15°N-55°N), it is founded that, the second mode of the EOF analysis exhibits interdecadal variations and indicate that the movement of EASM has three interdecadal abrupt changes in 1965, 1980 and 1994, respectively. Therefore, the three interdecadal abrupt changes bring the different processes of the EASM's movement and lead to the obvious change of the spatial distribution pattern of summer rainfall in East China directly, especially prior to 1965, the rainfall in the mid-lower reaches of the Yangtze River is much less than normal, while the precipitation is much more in South China, North China and Northeast China but with decreasing continuously since 1965. However, the rainfall in the mid-lower Yangtze Valley increases continually from 1980, especially from 1994 the rainfall in South China and the Yangtze Valley increases rapidly while the precipitation over North China was much less than normal. Therefore, in East China underwent from the pattern of south- drought and northern- waterlog before 1979 to south-waterlog and north- drought.

By using the humidity from AIRS data set, rainfall from TRMM GPI and wind from QSCAT wind as well as SST from Aqua/AMSR_E, We analyze the structure of summer intraseasonal oscillation (ISO) over western Pacific region in 2004. We find the signal of 20-90d oscillation in western Pacific originated from equatorial India ocean, which propagate eastward to Philippine sea, then propagate northwestward to south of China. The AIRS humidity data shows that the boundary layer moisture lead the mid-troposphere moisture during the ISO propagation. The positive SST anomaly may play an important role to moistening the boundary layer and induces the ISO propagation. Therefore, the intraseasonal SST anomaly could positively feed back to the atmosphere through moistening the boundary layer, destabilizing the troposphere, and contributing to the northwestward propagation of the ISO in western North Pacific. The character that the boundary moisture anomaly leads mid-troposphere moisture above ABL is not revealed by miosture depicted in ECMWF.

Utilizing the NECP/NCAR reanalysis data, the annual atmospheric circulation over East Asia from 1981 to 2000 is investigated. It is discovered that a zonal positive vorticity belt maintains to the south of Tibetan Plateau, due to the interaction of the plateau boundary layer and its neighboring free atmosphere. Particularly, there is an obvious topographic trough related to the positive vorticity near 90°E. According to this phenomenon, a Tibetan Plateau Topographic Trough Index (TPTTI) is defined in the paper over the key areas (80-90°E, 25°N). The index is proved to be effective in distinguishing between the characteristic of the Tibetan Plateau topographic trough (TPTT) and that of the Bay of Bengal Trough (BOBT). The annual variation of the TPTT is closely related to the plateau heating source, and the former's significant abrupt changes during April and June might be primarily induced by the seasonal sudden jump of the latter. In winter, the low-level anticyclone caused by the Tibetan plateau cooling is strengthened and superimposes the westerly wind that should have been strengthened by dynamic effect, which weakens the TPTT. However, in summer, the low-level cyclone resulting from the Tibetan plateau heating strengthens the circumferential westerly and deepens the TPTT. Further investigations indicate that there is a considerable relationship between the South China Sea summer monsoon onset and the evolution of the TPTT and the BOBT. The TPTT propagates southward and the vortex near Sir Lanka moves northward continuously, till they meet and interact over the Bay of Bengal. This is the direct process of the subtropical high belt splitting initially over Bay of Bengal and the establishment of the BOBT. Subsequently, the southwesterly wind becomes stronger and promotes the eastward retreat of subtropical high, causing the South China Sea summer monsoon bursts over the whole South China Sea.

Analysis based on remote sensing data and NCEP/NCAR reanalysis datasets finds that, on the basis of composing the most typical 'South-Born-South-Persisting' WPSH double ridges processes, anomaly 500 hPa stream field shows that the northern ridge vanishment is climatology, while there is a anomaly anticyclone in the south ridge, making its development and persistence and leading to the WPSH locate much southward than usual after the double ridges process ends. Further studies by the use of vorticity equation indicate that 150 hPa a anomaly anticyclone to the east of the WPSH south ridge region move westward, strengthening the minus vorticty advection of the south ridge region and changing the vertical motion over WPSH region. It not only changes the meridional wind distribution, leading to geostrophic vorticity advection intensify and the anomaly anticyclone develop, but also brings the diabatic heating distribute vertically asymmetrically, inducing a anomaly cyclone between the two ridges and a anomaly anticyclone above the south ridge. Conclusively, the general circulation on the upper level plays an important role in the double ridges process persistence.

Based on analysis of the temperature latitudinal deviation on middle troposphere on a climate basis, its seasonal cycle suggests that due to the Tibetan Plateau heating in spring, seasonal transition of the thermal difference between East Asia continent and West Pacific first takes place on the subtropical region, accompanied by the prevailing wind turning from northerly in winter to southerly in summer on low troposphere The precipitation takes place at the same time. This maybe indicates the East Asian subtropical summer monsoon onset. Consequently, it is advanced that the seasonal cycle formed by the zonal thermal contrast between Asian continent and western Pacific may be an independent driving force of East Asian subtropical monsoon.

Shortage of water supply in the growing season is the key condition to form a drought in the winter wheat production. Knowledge of risks brought about by the drought in winter wheat production is helpful in agricultural management. In this work, we investigated the intensities of droughts and probability of their occurrence as well as their impacts on the wheat yield based on water requirement by the crop and the nature of precipitation. Various techniques to comprehensively assess the risks of droughts in winter wheat production are exploited to develop the model of risk assessment of climatic droughts, the model of risk assessment of crop droughts, and the model of comprehensive risk assessment of crop-climatic droughts. The models are used in regional comprehensive risk assessment of droughts in winter wheat production in Northern China. A regionalization of risk levels is performed for this area. The results are helpful in adjusting the cropping arrangement and in carrying out agricultural managements to minimize or prevent the risk of droughts.

Drought is the serious agrometeorological disaster influences the growth of winter wheat in Henan Province, China. The main causes of drought formation in the province was preliminarily described based on factors such as geographical, monsoon circulation and the global climate background and then drought patterns that happened during last more than 40 years were analyzed in terms of negative departure percentage from averaged precipitation as indicators. Results show that heavy droughts are centralized in northeast part of the province and light droughts centralized in southwest part. The light ones took place every 3 years, medium ones did every 7 years and heavy ones every 10 years. This study is beneficial to winter wheat cropping planning and drought-prevention in Henan Province.

ECMWF daily reanalysis is applied to investigate 1961-2001 heat source/sink and the climate features in relation to the atmospheric heat distribution over the QTP (Qinghai-Tibetan Plateau) by means of the "inverse algorithm". Results suggest that 1) in March - September (October - February), the QTP acts as a heat (cold) source, the strongest being in June (December). For the region as a whole, the heat source feature lasts longer, with its intensity much higher compared to the cold source; 2) as shown in the heating vertical profile, the maximum heat source layer occurs dominantly between 500-600 hPa, but with the season-dependent heating strength and depth, and, in contrast, the cold source has its maximum layer and intensity varying as a function of time; 3) the horizontal distribution of the heat sources throughout the troposphere 1> (from surface to 100 hPa) is complicated, displaying noticeable regionality, i.e., the heat source changes faster in the western than in the eastern QTP, with the western source considerably stronger in April - August, and intensified quickly enough to show a 200 W/m² center in May, one month ahead of the eastern source. When July comes the regional heat source begins to weaken towards the south, during which the western source weakens faster, changing to a cold source in October, again one month earlier compared to the eastern counterpart; 4) since 1979 the seasonal variability of the heat source has shown climate transition signals, as clearly seen in 1990/91.

Changes of the order of 1%/decade or less are expected in the tropical ocean cloud amount due to global warming. Since the ocean is very dark in the visible and near infrared region of the spectrum, a change in the Earth reflectance is equivalent to a measure of the change in the cloud cover. A reliable measurement of such a small change in the visible requires a reference source which is much more stable than 1%/decade. A procedure is developed to use the sunlight reflected from Deep Convective Clouds (DCC) as a stable and readily available reference source for reflected light channels. The procedure uses the stability of the NIST traceable infrared radiometric calibration of the Atmospheric Infrared Sounder (AIRS) to create a stable DCC detection threshold, which assures a stable visible reflected reference signal. DCC are identified in the data as any IR footprint within ±30 degree latitude, where the brightness temperature in the 1231 cm^-1 window channel is 210K or less. The 90%tile value of the observed visible signal is used as reference to minimize the effect of under-filling the footprint. Typically 2000 DCC are identified each day during the daylight part of the orbit. The stability uncertainty in the DCC reference signal measured from the first four years of AIRS data is 0.02%/year, i.e. 0.2%/decade. The stability of the procedure demonstrated with AIRS is thus already better than the 1%/decade expected change in the cloud amount due to global warming. Extrapolated from four years to the expected 12 year lifetime of AIRS the trend uncertainty on the DCC measurements should decrease to 0.06%/decade. A 12 year record of the Earth reflectance stabilized with the DCC would allow for a very sensitive test of a change in the cloud amount. AIRS was launched on the EOS Aqua spacecraft in May 2002 into a 705 km polar sun-synchronous orbit with accurately maintained 1:30 PM ascending node. Essentially un-interrupted data are freely available since September 2002. The DCC are included in the AIRS Calibration Data Subset (ACDS).

We are developing a multi-robot science exploration architecture and system called the Telesupervised Adaptive Ocean Sensor Fleet (TAOSF). TAOSF uses a group of robotic boats (the OASIS platforms) to enable in-situ study of ocean surface and sub-surface phenomena. The OASIS boats are extended-deployment autonomous ocean surface vehicles, whose development is funded separately by the National Oceanic and Atmospheric Administration (NOAA). The TAOSF architecture provides an integrated approach to multi-vehicle coordination and sliding human-vehicle autonomy. It allows multiple mobile sensing assets to function in a cooperative fashion, and the operating mode of the vessels to range from autonomous control to teleoperated control. In this manner, TAOSF increases data-gathering effectiveness and science return while reducing demands on scientists for tasking, control, and monitoring. It combines and extends prior related work done by the authors and their institutions. The TAOSF architecture is applicable to other areas where multiple sensing assets are needed, including ecological forecasting, water management, carbon management, disaster management, coastal management, homeland security, and planetary exploration. The first field application chosen for TAOSF is the characterization of Harmful Algal Blooms (HABs). Several components of the TAOSF system have been tested, including the OASIS boats, the communications and control interfaces between the various hardware and software subsystems, and an airborne sensor validation system. Field tests in support of future HAB characterization were performed under controlled conditions, using rhodamine dye as a HAB simulant that was dispersed in a pond. In this paper, we describe the overall TAOSF architecture and its components, discuss the initial tests conducted and outline the next steps.

Observations of weather and climate yield demonstrated societal benefits, and have been officially part of U.S. government activities since Jefferson. Observing sensor networks contribute to real-time warnings of extreme weather, and to long-term analysis of endemic disease. To learn more about netcentric technologies and their role in observing sensor networks, the National Oceanic & Atmospheric Administration (NOAA) National Weather Service (NWS) and the American Institute of Aeronautics and Astronautics (AIAA) organized a seminar that examined System-of-Systems (SOS), Enterprise Architecture (EA) and Internet Protocol version 6 (IPv6) concepts, using two NOAA programs, the Global Earth Observation Integrated Data Environment (GEO-IDE) and the Integrated Ocean Observing System (IOOS), as examples. Further analysis of the seminar material shows the interrelationship of SOS and EA, with the enabling capability of IPv6 and the framework of a Service-Oriented Architecture (SOA), can help NOAA organize sensor systems-of-systems on a global scale in support of the Global Earth Observing System-of-Systems (GEOSS).

Under a recently-funded NASA Earth Science Technology Office (ESTO) award we are now designing, and will eventually implement, a sensor web architecture that couples future Earth observing systems with atmospheric, chemical, and oceanographic models and data assimilation systems. The end product will be a "sensor web simulator" (SWS), based upon the proposed architecture, that would objectively quantify the scientific return of a fully functional modeldriven meteorological sensor web. Our proposed work is based upon two previously-funded ESTO studies that have yielded a sensor web-based 2025 weather observing system architecture, and a preliminary SWS software architecture that had been funded by NASA's Revolutionary Aerospace Systems Concept (RASC) and other technology awards. Sensor Web observing systems have the potential to significantly improve our ability to monitor, understand, and predict the evolution of rapidly evolving, transient, or variable meteorological features and events. A revolutionary architectural characteristic that could substantially reduce meteorological forecast uncertainty is the use of targeted observations guided by advanced analytical techniques (e.g., prediction of ensemble variance). Simulation is essential: investing in the design and implementation of such a complex observing system would be very costly and almost certainly involve significant risk. A SWS would provide information systems engineers and Earth scientists with the ability to define and model candidate designs, and to quantitatively measure predictive forecast skill improvements. The SWS will serve as a necessary trade studies tool to: evaluate the impact of selecting different types and quantities of remote sensing and in situ sensors; characterize alternative platform vantage points and measurement modes; and to explore potential rules of interaction between sensors and weather forecast/data assimilation components to reduce model error growth and forecast uncertainty. We will demonstrate key SWS elements using a proposed future lidar wind measurement mission as a use case.

This paper describes the work being managed by the NASA Goddard Space Flight Center (GSFC) Information System Division (ISD) under a NASA Earth Science Technology Office (ESTO) Advanced Information System Technology (AIST) grant to develop a modular sensor web architecture which enables discovery of sensors and workflows that can create customized science via a high-level service-oriented architecture based on Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) web service standards. These capabilities serve as a prototype to a user-centric architecture for Global Earth Observing System of Systems (GEOSS). This work builds and extends previous sensor web efforts conducted at NASA/GSFC using the Earth Observing 1 (EO-1) satellite and other low-earth orbiting satellites.

To meet future earth system science challenges, NASA will develop constellations of smart satellites in sensor web configurations that provide timely on-demand data and analysis to users, and that be reconfigured based on the changing needs of science and available technology. Sensor webs can eclipse the value of disparate sensor components by reducing response time and increasing scientific value, especially when integrated with science analysis, data assimilation, prediction modeling and decision support tools. The prototype Land Information Sensor Web (LISW) is a project sponsored by NASA, trying to integrate the Land Information System (LIS) in a sensor web framework which allows for optimal 2-way information flow that enhances land surface modeling using sensor web observations, and in turn allows sensor web reconfiguration to minimize overall system uncertainty. This prototype is based on a simulated interactive sensor web, which is then used to exercise and optimize the sensor web - modeling interfaces. These synthetic experiments provide a controlled environment in which to examine the end-to-end performance of the prototype, the impact of various design sensor web design trade-offs and the eventual value of sensor webs for particular prediction or decision support. The Study of virtual Land Information Sensor Web (LISW) is expected to provide some necessary priori knowledge for designing and deploying the next generation Global Earth Observing System of systems (GEOSS). In this paper, the progress of the LISW study will be presented, especially in scenario experiment design, sensor web framework and uncertainties in current land surface modeling.

Accurate and precise satellite radiance measurements are important for data assimilations in numerical weather prediction models and climate change detection. Given the high-resolution spectral IASI measurements with high data quality, it allows us to assess the radiance measurements of 'heritage' instruments that share the same spectral region with IASI. In this study, we demonstrate the utility of the IASI radiances to evaluate the AVHRR IR channel observations. The IASI spectral radiances are convolved with the AVHRR SRFs (Spectral Response Functions) to produce the IASI-convolved AVHRR radiances. The co-registered AVHRR pixels inside each IASI pixel are averaged to compare with IASI. We analyzed one-orbit data on 21 June 2007, and preliminary comparison has been performed. Statistically, the temperature observed from AVHRR channels 4 and 5 is slightly warmer than IASI. The mean BT difference (IASI minus AVHRR) is -0.35K for channels 4 and -0.16 K for channel 5 with a standard deviation of 0.5K. The BT difference between IASI and AVHRR IR channels is scene-temperature dependent for both channels 4 and 5, possibly caused by the nonlinearity of detector. Both AVHRR Channel 4 and channel 5 show slightly symmetric dependence on scan angle with maximum differences of approximately ~0.2 K (AVHRR warmer than IASI) at both ends of the scan (with respect to the difference at nadir). However, the root cause of the bias still needs to be investigated by analyzing more datasets.

Based on 1979-2005 typhoon data and NCEP/DOE AMIP-II reanalysis, a study is performed of behaviors of tropical cyclones generated in the monsoon trough (MTTC hereinafter) in the western North Pacific as well as effects of the monsoon trough strength on their production. Evidence suggests that (1) during this period the MTTC yearly number experiences stages as follows: normal (1979~87), more MTTCs (1988~94), and fewer MTTCs (1995~2005); MTTC variation is marked by quasi-4 and -2 yearly periods, with 1994 as the change from more to fewer MTTCs in annual number; (2) in the years of anomalous MTTC number there are great difference in the onset/ending day and genesis position. In the years of fewer (more) MTTCs in comparison to mean, MTCC starts its activity later (earlier), terminating on an earlier (later) day, its genesis area is smaller (bigger), located south- (north-) and/or west- (eastward) of mean; 3) the ITCZ intensity affects the MTTC genesis position and yearly number. When the lower-level western North Pacific subtropical high is positioned south- (north-) of normal, cross-equatorial flows at Somali and 90~160⁰E are weaker (stronger), the monsoon trough is weaker (stronger) with its position south- and/or westward (north- and/or eastward) with respect to normal. At that time, in the tropopause, the south-Asian high is east- (westward) of mean and the oceanic upper-air trough is south- and/or westward (north- and/or eastward). And the distribution in the high and lower troposphere allows the small-value band of vertical wind shear to decrease (increase) for a smaller (bigger) domain for MTTC genesis, and convection is suppressed (intensified), leading to positive (negative) OLR anomalies over waters east of the Philippine so that MTTC is generated south- and/or westward (north- and/or eastward) relative to normal and MTTC annual number is anomalously smaller (greater).

The Climate features of summer sandstorms show that the season is rich in the disasters for the Gansu region, concentrated mainly in the Minqin, Dingxin and Jinta areas. The synoptic analysis of a rarely observed strong event indicates that in summer such dominant weather systems as the upper-level weak trough, shear line and thermal low are responsible for the sandstorm while in spring the tempest is generally triggered by large-scale systems. The upper-level jet's behaviors are not so manifest before the occurrence of the summertime sandstorm, with the jets suddenly intensified almost concurrently with its occurrence, which is one of the difficult points for forecasting the summer sandstorm. Now for the study we make use of satellite imagery and its sensings-based tracking as a more visualized tool for monitoring the onset, movement and coverage of the disaster.

In this paper, the variability characteristic and response to climate change of surface water resources, such as glacier, snow, lake and runoff of rivers in northwest China are analyzed by meteorological, hydrological and remote sensing data. The results show that the melting water has been increasing while glacier has been thinning and deteriorating along with global warming. The runoff of rivers that rely primarily on precipitation as water resource has significantly decreased. However the runoff of rivers originated from mountains shows significant increase as a result of increased melting water, which dominates the water supply, in addition to increased rainfalls since 80s. The water level of most lakes in Xinjiang has dramatically been rising and the areas are expanding because of increased rainfalls and melt water, in contrast to trend of lowering water level and shrinking areas for lakes in Inner Mongolia and Tibetan Plateau.

The trends of water vapor and methane in the stratosphere have been analyzed by using the HALOE data from 1992 to 2005. The variations of water vapor and methane averaged along latitude circle are analyzed in the levels 2hPa, 10hPa, 30hPa and 80hPa, which are taken as the upper, middle and lower stratosphere. Besides the seasonal and inter-annual variations, The trends of water vapor and methane in various levels are not the same. The variations of water vapor and methane generally are contrary. In the years when the water vapor increases, the methane decreases, and when the water vapor decreases, the methane increases.

HYDRA (Hyper-Spectral Data Research Application) is an interactive visualization and analysis tool developed for the interrogation and research of multi-and hyper-spectral satellite data. HYDRA has been used extensively around the world in the training of remote sensing scientists and in the development of applications. This experience represents valuable preparation for the development of new visualization and analysis tools needed for the upcoming GOES-R and NPOESS missions. It is listed by the WMO and NASA as a recommended visualization tool.

In this presentation, we report on the development and data analysis of a regional Multi-Filter Rotating Shadowband Radiometer Network for real-time monitoring of the atmosphere aerosols in support of long term and satellite validation measurements. The conventional radiometer calibration approach is to perform a Langley regression which requires a stable aerosol optical depth. The use of Langley regressions assumptions results in errors ranging from 30% to 50% in optical depth and requires numerous recalibrations for instrument drift. To improve on this approach, we have implemented a novel algorithm based on the ratio between the direct and diffuse radiance developed at NASA GISS [1, 2, 3] in which only the optical depth ratios during the calibration procedure are required to be stable. In particular, we show that this approach significantly improve optical depth time series measurements when compared to AERONET CIMEL. This improvement is traced to a statistical analysis which shows that the normalized optical depth variability is approximately three times larger than the optical depth ratio variability. Time series data analysis of retrieved total AOD's (fine and coarse) and angstrom coefficients from distributed sites are also presented and compared to CIMEL AOD's products.

Under specific external environment and surrounding circulations, a northern and a southern line are available at the same longitude in subtropical region on a synchronous basis, though the subtropical high has characteristic of single ridge in most areas at most of time. We define this phenomenon as 'the double ridges process'. It plays important roles on West Pacific Subtropical High (WPSH) discontinuous northward advancement and southward retreat, further on the second Meiyu period of Changjiang River basin. Furthermore, the moisture transport passage is changed when the process persists. The moisture is transported northward and converged to the north of the ridges, leading to two rainbelt formed. Subtropical high experiences double ridges process (DRP) nearly every year, of which the phase-locking and geographical preference result in DRP occurrence in the WPSH on a climatological basis. In this study, satellite data and the 43-yr mean climatology of NCEP/NCAR Reanalysis datasets are employed to examine the characteristics of WPSH DRP during the period of May to October. Six cases are found to occur during the period of late July to late September, indicating the preference time of the occurrences of WPSH DRP. Unexceptionally, each of them is characterized by a new-born ridge in the south of WPSH which persists several days before its vanishment and by the maintanence of the original one in the northern portion of WPSH.

Geostationary Simultaneous Nadir Observations (GSNOs) are collected for Earth Observing System (EOS) Atmospheric InfraRed Sounder (AIRS) onboard Aqua and a global array of geostationary imagers. The imagers compared in this study are GOES-12 and METEOSAT-8. A single polar-orbiting satellite can be used to intercalibrate any number of geostationary imagers. Using a high spectral resolution sensor, in this case AIRS, with absolute calibration to within 0.1K in most bands brings this method closer to an absolute reckoning of Imager calibration accuracy based on laboratory measurements of the instrument's spectral response. The gap-filling method presented is an adequate method of compensating for AIRS spectral gaps in nearly all geostationary bands for comparisons done at or near the equator. The US Standard Atmosphere is adequate for the most part, but an atmosphere either calculated from an AIRS retrieval or one more suited to the environment in which comparisons are being made, could produce even better results.

It is proposed to predict a reduction of the meteorological situation stability, as more inertial process, from an anticipatory change of the revealed structure character of optical inhomogeneities of a ground layer concerning a steady atmosphere. It opens up possibilities to use in forecast the method of optical anomalies detection which occurrence is caused by powerful local breaking of the atmosphere thermodynamic stability non-connected with the daily meteorological situation. They can be caused by sharp atmospheric processes of spontaneous-catastrophic character as well as man-caused disasters outside of the measurement zone when a possibility to predict a mechanical trajectory of such a distortion on the basis of similar predictors becomes a vital importance.