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

Bolten, John D.Evaluation of the Middle East and North AfricaLand Data Assimilation SystemBolten, John D. 1 ; Rodell, Matt 1 ; Zaitchik, Ben 11. Hydrological Sciences Lab, NASA GSFC, Greenbelt, MD,USAThe Middle East and North Africa (MENA) region isdominated by dry, warm deserts, areas of dense population,and inefficient use of fresh water resources. Due to thescarcity, high intensity, and short duration of rainfall in theMENA, the region is prone to hydroclimatic extremes thatare realized by devastating floods and times of drought.However, given its widespread water stress and theconsiderable demand for water, the MENA remains relativelypoorly monitored. This is due in part to the shortage ofmeteorological observations and the lack of data sharingbetween nations. As a result, the accurate monitoring of thedynamics of the water cycle in the MENA is difficult. TheLand Data Assimilation System for the MENA region(MENA LDAS) has been developed to provide regional,gridded fields of hydrological states and fluxes relevant forwater resources assessments. As an extension of the GlobalLand Data Assimilation System (GLDAS), the MENA LDASwas designed to aid in the identification and evaluation ofregional hydrological anomalies by synergistically combiningthe physically-based Catchment Land Surface Model (CLSM)with observations from several independent data productsincluding soil-water storage variations from the GravityRecovery and Climate Experiment (GRACE) and irrigationintensity derived from the Moderate Resolution ImagingSpectroradiometer (MODIS). In this fashion, we estimate themean and seasonal cycle of the water budget componentsacross the MENA.Borak, JordanA Dynamic Vegetation Aerodynamic RoughnessLength Database Developed From MODIS Imageryfor Improved Modeling of Global Land-Atmosphere ExchangesBorak, Jordan 1, 2 ; Jasinski, Michael F. 21. Earth System Science Interdisciplinary Center, Universityof Maryland, Greenbelt, MD, USA2. Hydrological Sciences Laboratory, NASA Goddard SpaceFlight Center, Greenbelt, MD, USAA new global database of seasonally varying vegetationaerodynamic roughness for momentum is being developedfor all global land areas by combining a physical model ofsurface drag partition with MODIS vegetation dataproducts. The approach, previously published in Jasinski etal. (2005) and Borak et al. (2005), utilizes Raupach’s (1994)roughness sublayer formulation, employing specific dragparameters developed for each MODIS land cover type. Theprocedure yields a unique vegetation roughness length (z0)and zero-plane displacement height (d0), on a pixel-by-pixelbasis, on the basis of land cover type, canopy area index, andcanopy height. Time series roughness quantities arecurrently being computed at 1 km resolution for all globalland regions for each MODIS 8-day compositing period forthe 10 complete years of data available for the MODISperiod of record (2001-1010). The new dynamic satellitebasedroughness fields, when employed within large-scalehydrologic, mesoscale and climate models, are expected toimprove representation of surface fluxes and boundary layercharacteristics, compared to models that utilize a traditionalroughness look-up table. The roughness formulation isvalidated using published roughness data from past fieldexperiments.Borsche, MichaelEstimation of high Resolution Land Surface HeatFlux Density Utilizing Geostationary Satellite DataBorsche, Michael 1 ; Loew, Alexander 11. Max Planck Institute for Meteorology, Hamburg,GermanyIn this study a flexible framework is presented whichallows for the estimation of land surface energy and waterfluxes based mainly on remote sensing satellite observationsas input. Major data input is taken from geostationarysatellite observations which are available at a very hightemporal (30min) and moderate spatial (5x5km) resolutionfrom the ISCCP reprocessing effort. The land surface schemeconsists of a single layer surface resistance model which isdriven by consistent input from remote sensing observationsand is constrained by remote sensing based observations ofsurface skin temperature and soil moisture. The coupling ofthe land surface model with a dynamic boundary layermodel implements an additional constraint to the surfaceflux estimations. The paper is focused on the evaluation ofthe estimated heat fluxes at the global scale. The heat fluxestimates are validated against globally selected eddycovariance measurements from stations of the FLUXNETflux station network. Specific experiments are presented thatdisentangle the various sources of uncertainties in the usedsatellite forcing data and propagate these uncertainties toerrors of latent heat fluxes. Finally we present a quasi-globalmulti-year latent heat flux record and its correspondinganomalies to demonstrate the climate applicability of theframework.Bounoua, LahouariCentury Scale Evaporation Trend: AnObservational StudyBounoua, Lahouari 11. Bospheric Sciences Branch, Code 691 SSED, Greenbelt,MD, USASeveral climate models with different complexityindicate that under increased CO2 forcing, runoff wouldincrease faster than precipitation overland. However,observations over large U.S watersheds indicate otherwise.This inconsistency between models and observationssuggests that there may be important feedbacks between41