Lecture6_Water budget_biomes

2005 goddard space flight center 41

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Unformatted text preview: Balance between evaporation, precipitation and runoff: Small available fresh water volume, + large fresh water fluxes = Short residence times: • • • • • atmosphere ~ 10 days rivers ~ 10 days biosphere ~ 1 week soil moisture ~ 2 months lakes & aquifers: variable • Need observations of: – Fresh water fluxes – Fresh water storage • Observations must meet predictive requirements: – global coverage, sampling and accuracy Center Goddard Space Flight 02 February 2005 45 Observing the Global Water Budget the Major Issues ► Measure and forecast all water cycle components ► Precipitation, evaporation, atmospheric transport, runoff, storage (ice and snow, rivers and lakes, soil, ground water) ► Related radiative issues (aerosols, effects of clouds, …) ► Measurement requirements (spatial, temporal, precision, accuracy) ► Water cycle variability with climate change ► Speed up of water cycle? ► Change in intensity of events? ► Sea level changes? ► Availability of clean fresh water ► Available water resources ► Effects of climate variability and change ► Ability to forecast 02 February 2005 Goddard Space Flight Center 46 Observing the Global Water Cycle Why Satellite Observations? Only space provides a systematic Earth view: Sea Surface Salinity 100 Years of Ship Observations 02 February 2005 Goddard Space Flight Center One Month of Aquarius 47 Observing the Global Water Cycle: What are we doing at Goddard? Measurement of components of the water cycle: Precipitation Evaporation Water vapor Runoff Polar ice Snow pack Ground water Ocean salinity Soil moisture Plus data assimilation of all components into NWP Plus an active program of supporting national needs through applications 02 February 2005 Goddard Space Flight Center 48 Global Precipitation Measurement TRMM • Global precipitation measurement with Global TRMM: a great leap forward! great • Quasi-operational measurement of global Quasi-operational global precipitation (with other satellites) (with – 10 ↔ 85 GHz radiometers (with other 10 (with other satellites) • • Needed improvements: – – – – 02 February 2005 – 13.6 precipitation radar – Global coverage (with other satellites) Global (with other satellites) – Resolution: variable – Accuracy: xyz mm/h Measure linkages: climate – weather – Measure water cycle – ocean circulation water Goddard Space Flight Center Better accuracy Spatial-temporal sampling Improved vertical resolution High latitude precipitation & snow 49 Global Precipitation Measurement: GPM 02 February 2005 Goddard Space Flight Center 50 Runoff / Surface Water Mission Stream Discharge and Surface Water Height from Space Motivation: • critical water cycle component • essential for water resource planning. • stream discharge and water height data are difficult to obtain outside US • find the missing continental discharge component Mission Concepts: Laser Altimetry Concept e.g. ICESat (GSFC) Radar Altimetry Concept e.g. Topex/Poseidon over Amazon R. Interferometer Concept (JPL) Targeted path Coincident w/ river reach 02 February 2005 Goddard Space Flight Center 51 Observing the Global Water Cycle I...
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This note was uploaded on 09/18/2013 for the course GEOG 100 taught by Professor Staff during the Fall '08 term at Maryland.

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