NASA’s return to the Moon coincides with explosive growth in exoplanet discovery. Missions are being formulated to search for habitable planets orbiting other stars, making this the ideal time to deploy an instrument suite to the lunar surface to help us recognize a habitable exoplanet when we see it. We present EarthShine, a technically mature, three-instrument suite to observe the whole Earth from the Moon as an exoplanet proxy. EarthShine data will validate and improve models critical for designing missions to image and characterize exoplanets, thus informing observing strategies for flagship missions to directly image exoplanets. EarthShine will answer interconnected questions in Earth and lunar science, exoplanets, and astrobiology, related to the credo “follow the water.” EarthShine can take advantage of current NASA programs to conduct science from the Moon with low-cost, mature space hardware to reduce risk and assure success. Like the 1968 Apollo Earthrise image of our home planet, lonely in the black sky, the appeal of EarthShine to a multidisciplinary array of researchers in Earth Science, Planetary Science, and astrophysics will maximize both its scientific impact and its impact on the general public.
Blowing snow plays an important role in the studies of the Earth’s cryosphere. Not only can
it affects the ice sheet mass balance and hydrological processes through redistributing surface mass
and driving spatial and temporal variations in snow accumulation, it also has a significant impact on
the long wave radiation budget both at the surface and at the top of the atmosphere. In this article,
we show that blowing snow has substantial impact on the Antarctic Outgoing Longwave Radiation
(OLR). Significant cloud-free OLR differences are observed between the clear and blowing snow
sky, with the sign and magnitude depending on season and time of the day.
Atmospheric mineral dust particles have significant effects on climate and the environment, and despite notable
advances in modeling and satellite and ground-based measurements, remain one of the major factors contributing
to large uncertainty in aerosol radiative forcing. We examine the Multi-angle Imaging SpectroRadiometer (MISR)
11+ year aerosol data record to demonstrate MISR's unique strengths and assess potential biases of MISR
products for dust study applications. In particular, we examine MISR's unique capabilities to 1) distinguish
dust aerosol from spherical aerosol types, 2) provide aerosol optical depths over bright desert source regions, and
3) provide high-resolution retrievals of dust plume heights and associated winds. We show examples of regional
and global MISR data products in dusty regions together with quantitative evaluations of product accuracies
through comparisons with independent data sources, and demonstrate applications of MISR data to dust regional
and climatological studies, such as dust property evolution during transport, dust source climatology in relation
to climatic factors, and dust source dynamics. The potential use of MISR radiance data to study dust properties
is also discussed.
A substantial upgrade of our previously developed MFRSR data analysis algorithm is presented. The new version of the algorithm features an automated cloud screening procedure based on optical thickness variability analysis. This technique is objective, computationally efficient and is able to detect short clear-sky intervals under broken cloud conditions. The performance of the method has been compared with that of AERONET cloud screening algorithm. Another new feature is the adoption of a bimodal gamma distribution as the aerosol particle size model. The size of the fine mode particles and a ratio between optical thicknesses of the two modes are retrievable. The algorithm has been tested on a multi-year dataset from the MFRSR network at the DOE Atmospheric Radiation Measurement (ARM) Program site in Southern Great Plains (SGP). The aerosol optical thicknesses (total, fine, and coarse) obtained from our analysis were successfully compared with the corresponding AERONET almucantar retrievals from a CIMEL sunphotometer colocated with the MFRSR at the SGP Central Facility. Geographical and seasonal variability of aerosol properties has been observed in the multi-instrument dataset from all SGP Extended Facilities for the year 2000. The geographical trends in the fine mode particle size appear to reflect differences in the PM2.5 to PM10 ratios obtained from EPA monitoring data. Long-term temporal variability has been studied on the 1992-1997 dataset from the SGP Central Facility. A significant trend has been detected in coarse mode aerosol optical thickness following the Mt. Pinatubo eruption in 1991, while the fine mode optical thickness exhibits only seasonal variations during that period.
We survey radiative Green function theory (1) in linear transport theory where numerical procedures are required to obtain specific results and (2) in the photon diffusion limit (large optical depths) where it is analytically tractable, at least for homogeneous plane-parallel media. We then describe two recent applications of Green function theory to passive cloud remote sensing in the presence of strong three-dimensional transport effects. Finally, we describe recent instrumental breakthroughs in 'off-beam' cloud lidar which is based on direct measurements of radiative Green functions with special attention to the data collected during the Shuttle-based Lidar In-space Technology Experiment (LITE) mission.
Taking a wavelet standpoint, we survey on the one hand various approaches to multifractal analysis, as a means of characterizing long-range correlations in data, and on the other hand various ways of statistically measuring anisotropy in 2D fields. In both instances, we present new and related techniques: (1) a simple multifractal analysis methodology based on Discrete Wavelet Transforms (DWTs), and (2) a specific DWT adapted to strongly anisotropic fields sampled on rectangular grids with large aspect ratios. This DWT uses a tensor product of the standard dyadic Haar basis (dividing ratio 2) and a non-standard triadic counterpart (dividing ratio 3) which includes the famous `French to-hat' wavelet. The new DWT is amenable to an anisotropic version of Multi-Resolution Analysis (MRA) in image processing where the natural support of the field is 2n pixels (vertically) by 3n pixels (horizontally), n being the number of levels in the MRA. The complete 2D basis has one scaling function and five wavelets. The new MRA is used in synthesis mode to generate random multifractal fields that mimic quite realistically the structure and distribution of boundary-layer clouds even though only a few parameters are used to control statistically the wavelet coefficients of the liquid water density field.
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