In the past few years, we have demonstrated how the surface return measured by the active
instruments onboard CloudSat and CALIPSO could be used to retrieve the optical depth and backscatter
phase function (lidar ratio) of aerosols and ice clouds. This methodology lead to the development of a
data fusion product publicly available at the ICARE archive center using the Synergized Optical Depth of
Aerosols and Ice Clouds (SODA & ICE) algorithm1. This algorithm, also allowing to derive ocean surface
wind speed, has been extended to include dense cloud surface return to analyze aerosol and cloud
properties above such clouds.
This low level data fusion of CALIPSO and CloudSat ocean surface echoes has been used by several
researchers to explore different research paths. Among them, we can cite:
• A new characterization of the lidar ratio of cirrus clouds2
• The analysis of the precipitable water and development of a new Millimeter-Wave Propagation
Model for the W-Band observations (EMPIRIMA3)
• The analysis of the lidar ratio of sea-spray aerosols4, and of Aerosol multilayer lidar ratio and
extinction5
• A contribution to the retrieval of the subsurface particulate backscatter coefficients of
phytoplankton particles6
In this paper, we present the main features of SODA & ICE, summarizing some of the results obtained.
This low level data fusion of CALIPSO and CloudSat ocean surface echoes has been used by several
researchers to explore different research paths. Among them, we can cite:
A new characterization of the lidar ratio of cirrus clouds2
The analysis of the precipitable water and development of a new Millimeter-Wave Propagation
Model for the W-Band observations (EMPIRIMA3)
The analysis of the lidar ratio of sea-spray aerosols4, and of Aerosol multilayer lidar ratio and
extinction5
A contribution to the retrieval of the subsurface particulate backscatter coefficients of
phytoplankton particles6
In this paper, we present the main features of SODA & ICE, summarizing some of the results obtained.
We use combined multi-year measurements from the surface and space for assessing the spatial and temporal distribution of aerosol properties within a large (~400x400 km) region centered on Cape Cod, Massachusetts, along the East Coast of the United States. The ground-based Aerosol Robotic Network (AERONET) measurements at Martha’s Vineyard Coastal Observatory (MVCO) site and Moderate Resolution Imaging Spectrometer (MODIS) sensors on board the Terra and Aqua satellites provide horizontal and temporal variations of aerosol optical depth, while the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) offers the altitudes of aerosol-layers. The combined ground-based and satellite measurements indicated several interesting features among which were the large differences in the aerosol properties observed in July and February. We applied the climatology of aerosol properties for designing the Two-Column Aerosol Project (TCAP), which is supported by the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program. The TCAP field campaign involves 12-month deployment (started July 1, 2012) of the ground-based ARM Mobile Facility (AMF) and Mobile Aerosol Observing System (MAOS) on Cape Cod and complimentary aerosol observations from two research aircraft: the DOE Gulfstream-1 (G-1) and the National Aeronautics and Space Administration (NASA) B200 King Air. Using results from the coordinated G-1 and B200 flights during the recent (July, 2012) Intensive Observation Period, we demonstrated that the G-1 in situ measurements and B200 active remote sensing can provide complementary information on the temporal and spatial changes of the aerosol properties off the coast of North America.
One month of MFRSR data collected at two sites in the central California (USA) region during the CARES campaign
are processed and the MFRSR-derived AODs at 500 nm wavelength are compared with available AODs provided by
AERONET measurements. We find that the MFRSR and AERONET AODs are small (~0.05) and comparable. A
reasonable quantitative agreement between column aerosol size distributions (up to 2 μm) from the MFRSR and
AERONET retrievals is illustrated as well. Analysis of the retrieved (MFRSR and AERONET) and in situ measured
aerosol size distributions suggests that the contribution of the coarse mode to aerosol optical properties is substantial for
several days. The results of a radiative closure experiment performed for the two sites and one-month period show a
favorable agreement between the calculated and measured broadband downwelling irradiances (bias does not exceed
about 3 Wm-2), and thus imply that the MFRSR-derived aerosol optical properties are reasonable.
We outline a new method, called the ratio method, developed to retrieve aerosol optical depth (AOD) under broken
cloud conditions and present validation results from sensitivity and case studies. Results of the sensitivity study
demonstrate that the ratio method, which exploits ratios of reflectances in the visible spectral range, has the potential for
accurate AOD retrievals under different observational conditions and random errors in input data. Also, we examine the
performance of the ratio method using aircraft data collected during the Cloud and Land Surface Interaction Campaign
(CLASIC) and the Cumulus Humilis Aerosol Processing Study (CHAPS). Results of the case study suggest that the ratio
method has the ability to retrieve AOD from multi-spectral aircraft observations of the reflected solar radiation.
Recent assessments of global climate change conclude that the radiative effect of aerosols is one of the largest uncertainties in our ability to predict future climate change. A myriad of new sensors and satellite missions are being designed to address this major question confronting credible prediction of climate change. The NASA Langley Airborne A-Band Spectrometer (LAABS) is a recently developed aircraft instrument that provides high spectral resolution (~0.03 nm) radiance measurements of reflected sunlight over the oxygen A-band spectral region centered near 765 nm. High resolution O2 A-band spectrometry of reflected sunlight is a promising new approach for remote sensing of aerosol and cloud optical properties. While the LAABS instrument provides valuable data on a stand-alone basis, greater scientific return may be realized by combining the A-band spectra with coincident lidar measurements that supply additional information on the vertical distribution of the aerosol. In particular, an instrument suite that combines LAABS with the new airborne High Spectral Resolution Lidar (HSRL) has the potential to provide a comprehensive suite of aerosol and cloud optical property measurements never before achieved. In this paper, we investigate the combined use of LAABS and HSRL measurements to infer aerosol single scatter albedo. We explore the information content of the O2 A-band reflectance spectra and, in particular, the advantages offered by high resolution A-band spectrometers such as LAABS. The approach for combined LAABS/HSRL retrievals is described and results from simulation studies are presented to illustrate their potential for retrieval of single scatter albedo.
Richard Ferrare, Edward Browell, Syed Ismail, Susan Kooi, Vince Brackett, Marian Clayton, Anthony Notari, Carolyn Butler, John Barrick, Glenn Diskin, Barry Lesht, Frank Schmidlin, Dave Turner, David Whiteman, Larry Miloshevich
Measurements of water vapor profiles over the Southern Great Plains acquired by two different lidars are presented. NASA's airborne DIAL Lidar Atmospheric Sensing Experiment (LASE) system measured water vapor, aerosol, and cloud profiles during the ARM/FIRE Water Vapor Experiment (AFWEX) in November-December 2000 and during the International H2O Project (IHOP) in May-June 2002. LASE measurements acquired during AFWEX are used to characterize upper troposphere water vapor measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. LASE measurements acquired during IHOP are being used to better understand the influence water vapor variability on the initiation of deep convection and to improve the quantification and prediction of precipitation associated with these storms. The automated Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Raman Lidar (CARL) has been routinely measuring profiles of water vapor mixing ratio, relative humidity, aerosol extinction, aerosol backscattering, and aerosol and cloud depolarization during both daytime and nighttime operations. Aerosol and water vapor profiles acquired since March 1998 are used to investigate the seasonal variability of the vertical distributions of water vapor and aerosols.
The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounding Testbed-Interferometer (NAST-I), is the infrared component of a suite of airborne infrared and microwave spectrometers, developed for the Integrated Program Office (IPO), that has been flying on high-altitude aircraft as part of the risk reduction effort for NPOESS. It is a high spectral resolution (0.25 cm-1, unapodized) and high spatial resolution (~2 km, nadir) cross-track scanning (~ 45 km swath width, at 20 km aircraft altitude) Fourier Transform Spectrometer (FTS) observing within the 3.7 - 16.1 micron spectral range. In addition to characterizing the atmospheric thermal and moisture structure and providing information on radiatively active trace gases (e.g. O3 & CO) during field experiments, NAST-I measurements greatly contribute toward instrument and forward model pre-launch specification optimization (i.e., for the Cross-track Infrared Sounder, CrIS, to fly on NPOESS) and will enhance post-launch calibration/validation activities for CrIS as well as for other future advanced atmospheric spaceborne sensors (e.g., the EOS AIRS, CERES, MODIS, MOPITT, & TES instruments). In this paper, we investigate some of the challenges associated with validating infrared spectral radiances obtained from remote sensing measurements and forward model simulations. Specifically, measured infrared spectral radiances are compared with radiance calculations performed using a Line by Line forward radiative transfer model based on nearly-coincident temperature and water vapor profiles observed with several independent in-situ, passive, and active measurement systems.
The Goddard mobile lidar was deployed at Cannon Air Force Base near Clovis, New Mexico during the Spring of 1990. Measurements of stratospheric ozone and temperature were made over a period of six weeks. Data from the lidar system is compared with data from a balloon-borne, ultraviolet instrument launched from nearby Ft. Sumner, New Mexico. Along with several improvements to this instrument which are now underway, a second lidar dedicated to temperature and aerosol measurements is now being developed.
As a part of the international Network for the Detection of Stratospheric Change, Goddard Space Flight Center has developed a mobile differential absorption lidar capable of making precise and accurate measurements in the stratosphere between 20 and 45 km. We present in this paper a description of the instrument, a discussion of the data analysis,
and some results from an intercomparison held at JPL's Table Mountain Observatory in California during October and November 1988.
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