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

adiometers in geostationary Earth orbit (e.g., Joyce et al.2004, J. Hydrometeorol; Huffman et al. 1997, J.Hydrometeorol; Ushio et al. 2009, J. Meteorol. Soc. Jpn.).Although utilization of these datasets for flood andlandslide analysis/prediction has started, it is still in theexperimental stage because of the poor performance ofsatellite estimates in heavy rainfall over mountainousregions. Kubota et al. (2009, J. Meteorol. Soc. Jpn.) showedworst verification results over mountainous regions, inparticular, areas with frequently heavy orographic rainfall,comparing the satellite rainfall estimates around Japan withreference to a ground-radar dataset calibrated by rain gaugesprovided by the Japan Meteorological Agency. Theysuggested that one of main reasons for these errors isunderestimation of MWR algorithms for orographic heavyrainfall over Japan. In this paper, we improve theperformance of estimates by the Global Satellite Mapping ofPrecipitation (GSMaP) estimates from MWRs (Aonashi et al.2009, J. Meteorol. Soc. Jpn.; Kubota et al. 2007, IEEE Trans.Geosci. Remote Sens.) for orographic heavy rainfall. TheGSMaP algorithm consists of the forward calculation part tocalculate the lookup tables (LUTs) showing the relationshipbetween rainfall rates and brightness temperatures (Tbs)with an radiative transfer model (RTM), and the retrievalpart to estimate precipitation rates from the observed Tbsusing the LUTs. We dynamically select whether LUTscalculated from “original” precipitation profiles or thosefrom “orographic” precipitation profiles based on theorographically forced upward vertical motion and surfacemoisture flux convergence. Rainfall estimates from therevised GSMaP algorithm are much better agreement withPR estimates than those from the original GSMaPalgorithm.Shum, C. K.SURFACE FLOOD AND SMALL WATER BODYMONITORING USING RADAR ALTIMETRY:PROSPECTS FOR SWOTShum, C. K. 1 ; Tseng, Kuo-Hsin 1 ; Kuo, Chungyen 2 ; Alsdorf,Douglas 1 ; Calmant, Stephane 3 ; Duan, Jianbin 1 ; Lee,Hyongki 4 ; Yi, Yuchan 11. School of Earth Sciences, Ohio State University,Columbus, OH, USA2. School of Earth Sciences, The Ohio State University,Columbus, Taiwan3. Institut de Recherche pour le Developpement, LEGOS,Toulouse, France4. Civil and Environmental Engineering, University ofHouston, Houston, TX, USAThe planned Surface Water and Ocean Topography(SWOT) wide-swath interferometric altimetry mission isanticipated to revolutionize hydrologic surface watermeasurement from space, with unprecedented spatialresolution, sampling and accuracy. While off-nadir repeatpassradar interferometric SAR (InSAR), when combinedwith satellite radar altimetry to provide needed verticalreference, is capable of measuring high spatial resolution(~40 m) dh/dx surface water changes at SAR acquisitiontimes, unlike SWOT, it could only measure vegetatedwetlands or lakes which allow double-bounced radar signaldetections. This contribution addresses challenging researchobjectives to improve contemporary pulse-limited nadirradar altimetry to enable accurate measurements ofspaceborne water level changes over relatively small waterbodies (< 1 km width, which is much smaller than the 1-Hzdata sampling with footprints of several km), using radarwaveform retracking techniques, exploiting higher sampledaltimeter data (20 Hz for Jason-2), and mitigation ofspurious waveforms caused by contamination of waveformsover non-water surface, especially those with steep or roughterrains. Here we study the feasibility of extending thecapability of contemporary radar altimeters (20-Hz Jason-2,the planned 40-Hz AltiKa, and the mini-swath CryoSatSAR/SIRAL data) for surface flood and inland small waterbody monitoring and hydraulic studies. Demonstrationstudies include for proof-of-concept timely monitoring offlood episodes, flood heights and extents using altimetryand other data sets (MODIS, GRACE), including 1997 RedRiver floods, the 2009 Amazon record flood on Rio Negro,the 2010 flood in Pakistan and China, the 2011 Australian,Memphis and Thailand floods. Demonstration waveformretracking/improvement studies over small inland waterbodies include seasonally inundated Bajhang River, Taiwan,with varying river width at 100 m to 2 km, Poyang Lake,China, and other water bodies, indicating that using bothalternate retrackers (e.g., threshold retrackers) and waveformediting/mitigation techniques based on empirical surfaceresponse data from radar backscatters, resulted in betterImprovement Percentages (IMPs) agreement with availablein situ gage measurements, as compared to the onboardretracked measurements. Finally, this study intends toaddress the feasibility of development of an improved apriori seasonally varying water masks in preparation for theSWOT mission.Singh, AmitASSESSMENT OF MORPHOTECTONICINFLUENCES ON HYDROLOGICALENVIRONMENT IN VICINITY OF AN ACTIVEFAULTSingh, Amit 1 ; Mukherjee, Saumitra 11. School of Environmental Sciences, Jawaharlal NehruUniversity, New Delhi, IndiaStudying effects of faulted zones in shaping thehydrological environment of any landscape in a long run isdifficult, though these can play a crucial role in regulatingthe flow and accumulation of water. While aquifer rechargeis directly influenced by the structural changes associatedwith tectonic activity, surface flow may also be influenceddepending upon the topography. While planning for waterresource management, groundwater remediation orhydrological restoration it is imperative to understand andsuitably include these influences to derive maximumbenefit. This study aimed at characterization of surface as134