2012 AGU Chapman Conference on Remote Sensing of the ...

interferometric synthetic aperture radar, KaRIn, thatproduces centimetric-level elevation and brightness mapsacross a 100 km swath, sufficient to map the majority of theEarth in a 22-day orbital cycle. The SWOT mission alsoproposes to carry payload elements similar to the Jasonaltimetermissions, including a nadir altimeter andwater-vapor radiometer, as well as a GPS receiver and aDORIS receiver for precision orbit determination. In thispaper, we discuss many of the recent developments in thedesign of the mission. The flight system and mission systemarchitectures have been optimized to support the significantdata volumes of full resolution imaging (several TB/day)necessary for surface water imaging, while allowingflexibility to change the imaged areas as science needs evolve.The flight system architecture itself is designed around theboth the critical thermal and pointing stability requirementsof the elevation measurements, while also optimizing theaccommodation of the other instruments. We also discussthe development challenges facing the mission, which istargeting a 2019 launch.http://swot.jpl.nasa.gov/Pressel, Kyle G.Scale Invariance of the Water Vapor Field Observedby the Atmospheric Infrared SounderPressel, Kyle G. 1, 2 ; Collins, William D. 1, 21. Earth and Planetary Sciences, University of California,Berkeley, Berkeley, CA, USA2. Lawrence Berkeley National Laboratory, Berkeley, CA,USAThe Atmospheric Infrared Sounder (AIRS) providestwice daily physical retrievals of water vapor mass mixingratio with nearly global coverage in clear and partially cloudysky conditions. AIRS retrievals have nominally 50km nadirresolution which allows a characterization of the scaledependence of the water vapor field at scales smaller thanthe smallest resolved scales in modern global climate models(GCMs). The observed scale dependence can be used as anempirical basis for the assessment of the water vapor field inGCM simulations. We will present an analysis of the spatialscale dependence of the AIRS retrieved water vapor fieldthrough the first order structure function. The first orderstructure function relates the mean of spatial fluctuations,also know as increments, to scale. If the structure functionexhibits power law dependence on scale then the fieldexhibits a type of symmetry known as scale invariance. Manynatural systems exhibit scale invariance, and for turbulentflows the power law exponents which characterize the scaleinvariance appear to be a nearly universal property of broadclasses of flows. In particular we compute the first structurefunctions for scales between 50km and 500km of the AIRSlevel 2 water vapor field computed over 10 degree latitudelongitude boxes centered every 2 degrees latitude andlongitude between 60S and 60N. Special attention is given toassessing the isotropy of the increment field and quality ofstructure function power law fits. The results suggest thatthe atmospheric water vapor field exhibits widespread scaleinvariance with a power law fit explaining at least 90% ofvariance in the structure function in more than 99% ofcomputed structure functions on the 925hPa and 500hPapressure surfaces. Comparing structure functions computedusing increments in orthogonal directions allows theisotropy of the increment field to be investigated. Ourresults show that power law exponents exponents computedfrom structure functions in the satellite along and acrossdirections rarely exceed 0.1 in magnitude, which suggests theincrement field is approximately isotropic. The resultssuggest that power law exponents exhibit significant verticalvariability but very little horizontal variability. In particularit is shown that exponents vary from less than 1/2 in theboundary layer to greater than 1/2 in the middletroposphere. Also, it is shown that diurnal variations incomputed exponents are larger over land areas than over theocean and larger in the boundary layer than in the middletroposphere. The result that scaling exponents on aparticular pressure surface exhibit relatively little variabilitysuggests that a quasi-universal exponent may characterizethe scale invariance of water vapor on a particular pressuresurface. The smallest scale investigated in this presentationwas only limited by the resolution of AIRS, hence it is likelythat the observed scaling extends to even smaller scales. Thissuggests that the observed scaling may be used as a basis forthe stochastic parameterization of the water vapor field inGCMs. In situ measurements are need to confirm theseresults at smaller scales.Qiu, GuoyuEstimation of evapotranspiration (ET) and itspartition into evaporation (Es) and transpiration(Ec) based on three-temperature model andMODIS productsTian, Fei 1 ; Qiu, Guoyu 2 ; Yang, Yonghui 31. Beijing Normal University, Beijing, China2. Peking University, Shenzhen, China3. Chinese Academy of Sciences, Shijiazhuang, ChinaET is one of the most important land surface processesfor terrestrial ecosystems that can help us to understandhydrological processes, and manage water resources, soresearches on ET are focused by scientists around theworld.The Heihe River Catchment is the second largestinland river catchment in northwestern China. Due tooverexploitation of water resources, environmental worsenedand downstream was transforming into one of China’s“sandstorm cradles”. To restore the ecosystem, EcologicalWater Conveyances Project (EWCP) has been conducted.While how much water is used for oasis sustainabledevelopment is not clear, an accurate estimate oftranspiration is necessary. So three temperature model (3Tmodel) based on MODIS products (MOD11A2, MOD13A2,MCD43B1) were used to evaluate evapotranspiration andpartition it into evaporation and transpiration.Resultsindicated that yearly averaged ET, Es and Ec distributiondecreased from upstream Qilian mountain area (more than600 mm/a) to the downstream desert region in the north119