Global Terrestrial Evapotranspiration from Optical and Microwave - PowerPoint PPT Presentation

Global Terrestrial Evapotranspiration from Optical and Microwave Satellite Observations - Preliminary Results Li Jia RADI-CAS, Beijing, China (jiali@radi.ac.cn) C. Zheng, G.C. Hu, J. Zhou, Z. Li, Y. Cui, J. Lu, K. Wang, Q. Liu, M. Menenti

Outline • Background • ETMonitor • Validation and Intercomparison • Application Perspectives • Summary

• ET is a term involving Surface Energy Balance (SEB) and Surface Water Balance (SWB) (Figures adapted from Wagner) More than 50% of the solar energy Global land evapotranspiration (ET) absorbed by land surfaces is returns about 60% of annual land currently used to evaporate water. precipitation to the atmosphere.

Remote Sensing ET Products ET Product Spatial Temporal Spatial Theory Input RS Data OutPut Res. Step Coverage LAI, FVC, Albedo, LandSAF 30 min, Europe, H-TESSEL ET 3–5 km Downwelling (MSG) ET daily Africa, SVAT scheme Fluxes, LULC, South Snow Cover America MODIS ET LAI/fPAR, Albedo, ET, LE, 1 km 8 days Global P-M LULC Potential ET, (MOD16) Potential LE ET-VUA P-T LST, Vegetation ET, 25 km daily Global Optical Depth, (GLEAM) + Soil Water Interception Precipitation, Balance Loss Soil Moisture, Snow Depth, LULC LST, NDVI, ET ET-ITC 5 km monthly Global SEB Albedo, LULC 1 km Global Multi-Param. LAI, Albedo, ET, E, T, ETMonitor daily Precipitation, Interception 250 m Regional / (incl. Soil Moisture, Loss, 25 m Basin Shuttleworth Snow Cover, Potential ET, scale –Wallace, etc) LULC ET Deficit

ETMonitor • Involving energy & water balance, and plant physiology processes • Combining optical and microwave remote sensing observations

Global actual ET from ETMonitor

ETMon onitor or: Validati tion Cropland (semi-humid region) Cropland (semi-arid region) 7 7 6 5 2009-2011 2008-2010 EC ETMonitor EC ETMonitor (a) Yingke (d) Guantao 6 ETMonitor Remotely Sensed ET (mm/d) 6 ETMonitor: Linear Remotely Sensed ET (mm/d) ETMonitor ETMonitor: Linear 5 4 MOD16 MOD16 MOD16 MOD16 5 5 MOD16: Linear MOD16: Linear 4 ET (mm/d) ET (mm/d) 3 4 4 3 3 3 2 2 2 2 1 1 1 1 (a) Yingke (d) Guantao 0 0 0 0 0 180 360 540 720 900 1080 0 1 2 3 4 5 6 7 0 180 360 540 720 900 1080 0 1 2 3 4 5 Days since Jan 1, 2009 EC (mm/d) EC (mm/d) Days since Jan 1, 2008 Alpine grassland Cropland + orchard (semi-humid region) 5 6 6 6 2009-2011 2008-2010 ETMonitor EC EC ETMonitor (e) Miyun (b) A'rou ETMonitor Remotely Sensed ET (mm/d) ETMonitor: Linear ETMonitor Remotely Sensed ET (mm/d) ETMonitor: Linear 5 5 5 4 MOD16 MOD16 MOD16 MOD16 MOD16: Linear MOD16: Linear 4 4 4 ET (mm/d) ET (mm/d) 3 3 3 3 2 2 2 2 1 1 1 1 (e) Miyun (b) A'rou 0 0 0 0 0 1 2 3 4 5 0 180 360 540 720 900 1080 0 180 360 540 720 900 1080 0 1 2 3 4 5 6 Days since Jan 1, 2008 EC (mm/d) Days since Jan 1, 2009 EC (mm/d) Alpine forest 4 4 2009-2011 China (Hai River Basin, Heihe EC ETMonitor (c) Guantan ETMonitor Remotely Sensed ET (mm/d) ETMonitor: Linear MOD16 MOD16 3 3 River Basin) MOD16: Linear ET (mm/d) 2 2 1 1 (c) Guantan

ETMon onitor or: Validati tion China (Tibetan Plateau, Yun-Gui Plateau) Alpine forest (Linzhi) Alpine grassland (Maqu) 5 5 5 5 EC EC 2013 y = 1.1038x - 0.0625 2013 y = 0.8291x - 0.0331 ETMonitor ETMonitor R 2 = 0.7684 R 2 = 0.7614 4 4 4 4 ETMonitor (mm/d) ETMonitor (mm/d) ET (mm/d) ET (mm/d) 3 3 3 3 2 2 2 2 1 1 1 1 0 0 0 0 0 60 120 180 240 300 360 0 60 120 180 240 300 360 0 1 2 3 4 5 0 1 2 3 4 5 DOY EC ET (mm/d) DOY EC ET (mm/d) Rain forest (Xishuangbanna, monthly) Alpine grassland - wetland (MS3478) 110 5 5 2013 EC 2013 ETMonitor (mm/month) ETMonitor 100 4 4 ETMonitor (mm/d) y = 0.4011x + 0.6008 R 2 = 0.2365 ET (mm/d) 90 3 3 80 2 2 y = 1.1034x - 18.464 1 1 70 R 2 = 0.7451 0 0 60 0 60 120 180 240 300 360 0 1 2 3 4 5 60 70 80 90 100 110 DOY EC ET (mm/d) EC ET(mm/month)

ETMon onitor or: Validati tion Europe & Africa Grassland (Cabauw) Forest (Loobos) 5 4 4 4 EC ET by ETMonitor (mm/d) ET by ETMonitor (mm/d) 2012 2012 EC ETMonitor 4 ETMonitor 3 3 3 ET (mm/d) ET (mm/d) MSG MSG 3 2 2 2 2 y = 1.06x - 0.28 y = 0.85x + 0.36 R 2 = 0.95 R 2 = 0.74 1 1 1 1 RMSE = 0.32 mm/d RMSE = 0.46 mm/d 0 0 0 0 0 1 2 3 4 0 1 2 3 4 0 60 120 180 240 300 360 0 60 120 180 240 300 360 Observed ET (mm/d) Observed ET (mm/d) Days since Jan 1, 2012 Days since Jan 1, 2012 Grassland (IE-Dri) Forest (CZ-BK1) 4 EC 4 5 5 EC y = 0.7528x - 0.2184 2010 2010 ETMonitor ETMonitor (mm/d) ETMonitor R 2 = 0.7138 ETMonitor (mm/d) 4 4 3 MOD16 3 MOD16 ET (mm/d) ET (mm/d) 3 3 2 2 2 2 y = 0.8461x + 0.0493 R 2 = 0.7648 1 1 1 1 0 0 0 0 0 60 120 180 240 300 360 0 1 2 3 4 0 1 2 3 4 5 0 60 120 180 240 300 360 DOY EC ET (mm/d) EC ET (mm/d) DOY Savanna (ZA-Kru) Savanna (ES-LMa) 5 5 5 5 EC 2010 2010 EC ETMonitor y = 0.481x + 0.7543 ETMonitor (mm/d) 4 4 4 4 ETMonitor ETMonitor (mm/d) R 2 = 0.4537 MOD16 ET (mm/d) 3 3 ET (mm/d) 3 3 y = 0.5664x + 1.1054 2 2 R 2 = 0.394 2 2 1 1 1 1 0 0 0 60 120 180 240 300 360 0 1 2 3 4 5 0 0 0 1 2 3 4 5 DOY EC ET (mm/d) 0 30 60 90 120 150 180 210 240 270 EC ET (mm/d) DOY

Inter ercomparison on with th RS E ET p product cts ETMonitor (1km, daily) MOD16 (1km, 8-day) Global ET, 2010 actual total mm/yr SEBS (ITC) (0.05 ° , monthly)

Inter ercomparison on with th RS E ET p product cts Annual total actual ET in Africa in 2010 MSG ETMonitor ET from ETMonitor is more closely related to MSG ET MOD16 SEBS from geostationary satellite mm/yr observation

LAI and S SM deter ermine t e the E e ET patter ern 1 7 LAI ETMonitor, SM 0 0 July 2010 DOY=193 ASCAT, DOY=193 mm/yr

ETMonitor: High Resolution DMC based ET (daily, 25m), Flevoland, NL May, 2013 June, 2013 July, 2013 16 May Aug, 2013 Sept, 2013 14 Jun. 12 Jul. Frequency (%) Aug. 10 Sep. 8 6 4 2 0 0 20 40 60 80 100 120 140 160 ET (mm/month)

ETMonitor: High Resolution DMC based ET (daily, 25m), Validation Cabauw (grassland) 2012–2013 (daily) EC 6 ET by ETMonitor (mm/d) 6 ETMonitor 5 5 ET (mm/d) 4 4 3 3 y = 1.20x - 0.58 2 R 2 = 0.75 2 RMSE = 0.55 mm/d 1 1 0 0 0 1 2 3 4 5 6 0 120 240 360 480 600 720 Observed ET (mm/d) Days since Jan 1, 2012 Loobos (Forest) 2012–2013 (daily) EC 6 ET by ETMonitor (mm/d) 6 ETMonitor 5 5 ET (mm/d) 4 4 3 3 y = 0.99x - 0.02 2 R 2 = 0.45 2 RMSE = 0.74 mm/d 1 1 0 0 0 1 2 3 4 5 6 0 120 240 360 480 600 720 Observed ET (mm/d) Days since Jan 1, 2012

Application Perspectives ETMonitor: Water Demand and Deficit ET Deficit (ETpot – ETact) Drought Monitoring (China, 2011): • Yangtze River Basin • Inner-Mongolia YRB

Application Perspectives ETMonitor: Water Demand and Deficit P - ET, 2010

Summary • Both vegetation and sol moisture patterns determine the ET distribution. • Accuracy and spatial resolution of soil moisture are critical for ET estimate at corresponding scales. • Sentinel 2 will contribute to ET estimate at higher resolution both in space and in time. • Better ET product will benefit to water resource management in terms of drought monitoring, water productivity, etc. • Global Validation is needed

References • Hu G.C. and L. Jia, 2015, Monitoring of Evapotranspiration in a Semi-Arid Inland River Basin by Combining Microwave and Optical Remote Sensing Observations, Remote Sensing, 7(3), 3056-3087; doi:10.3390/rs70303056. Hu G.C., L. Jia*, Menenti M. 2015, Comparison of MOD16 and LSA-SAF MSG • evapotranspiration products over Europe for 2011. Remote Sensing of Environment, 156, 510–526, doi:10.1016/j.rse.2014.10.017. • Cui Y.K., L. Jia*, G.C. Hu, and J. Zhou, 2015, Mapping of Interception Loss of Vegetation in the Heihe River Basin of China Using Remote Sensing Observations, IEEE Geoscience and Remote Sensing Letters (IEEE GRSL), 12(1), 23 – 27; doi:10.1109/LGRS.2014.2324635. • Cui Y.K., L. Jia*, 2014, A Modified Gash Model for Estimating Rainfall Interception Loss of Forest Using Remote Sensing Observations at Regional Scale, Water, 2014, 6(4), 993- 1012; doi:10.3390/w60 • Cui Y.K., L. Jia*, 2015, Regional Land Surface Evapotranspiration from ETMonitor+ by Assimilating Surface Soil Moisture Data, manuscript to be submitted to Agriculture & Forest Meteorology.

Thank you for your attention ! Li Jia Team Earth Observation for Water Cycle State Key Laboratory of Remote Sensing Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences jiali@radi.ac.cn http://eo-water.radi.ac.cn/en (under construction)