simulation and satellite observation Yohei Sawada Ph.D Candidate River and Environmental Engineering Laboratory, Department of Civil Engineering, the University of Tokyo 2016/3/2 Asian Water Cycle Symposium 2016
of droughts? Natural climate variability Precipitation deficiency, high temperature etc… Soil water deficiency Plant water stress, reduced biomass and yield Reduced stream flow, inflow to reservoirs, Groundwater deficiency, …… Economic, Social, and Environmental impacts [from National Drought Mitigation Center, University of Nebraska-Lincoln, USA] See also [Mishra and Singh, 2010] Meteorological Ecological Hydrological Drought is multi-sector and multi-scale phenomena. Couplings between hydrology and ecology are important to quantify droughts.
Initial Condition Parameter Optimization t e.g., Soil moisture Even if the model were perfect, we cannot forecast very well without good initial conditions and model parameters. How can we get the observations to improve our forecast in the ungauged areas??
of droughts? Natural climate variability Precipitation deficiency, high temperature etc… Soil water deficiency Plant water stress, reduced biomass and yield Reduced stream flow, inflow to reservoirs, Groundwater deficiency, …… Economic, Social, and Environmental impacts Meteorological Ecological Hydrological
model) Dynamic Vegetation Model (DVM) WEB-DHM-Veg can simulate soil moisture, groundwater, river discharge, and vegetation growth (and their interactions).
rainfall JRA25 reanalysis [Onogi et al., 2007] LAI Soil Moisture Groundwater River discharge Satellite LAI (AVHRR) Calibration & Validation In-situ river discharge Calibration & Validation Agricultural Drought Index Nationwide crop production & Reports about past droughts Validation Hydrological Drought Index Drought Analysis Drought Indices - Standardized Anomaly Index (SA index) – [Jaranilla-Sanchez et al., 2011]
LAI and Orange:nationwide crop production The drought index calculated from the model-estimated annual peak of leaf area index correlates well with the drought index from nationwide annual crop production. R =0.89 Drought Nash = 0.66 R = 0.80 River Discharge at Jendouba site Blue: Simulated river discharge Red: Observed river discharge Bar: Rainfall [Sawada et al., 2014, Water Resour. Res.]
River discharge Gray: Groundwater level Green: Leaf Area Index Drought Agricultural Drought Hydrological Drought Historic agricultural droughts predominantly occurred prior to hydrological droughts and the hydrological drought lasted much longer, even after crop production has recovered. [Sawada et al., 2014, Water Resour. Res.]
Initial Condition Parameter Optimization t e.g., Soil moisture How can we get the observations to train the numerical simulation in the ungauged areas ? Satellite!!
microwave region Radiation from soil depends on Surface Soil Moisture Attenuation by canopy Radiation from canopy depend on Vegetation water content • Microwave brightness temperature is influenced by surface soil moisture, vegetation water content, and temperature [e.g., Paloscia and Pampaloni, 1988] • It is not strongly influenced by atmospheric condition By assimilating this data, we can improve the skill of eco-hydrological model to simultaneously calculate soil moisture and vegetation dynamics. AMSR-E AMSR2
Climatorogy Green: Horn of Africa drought (reanalysis) Leaf Area Index timeseries CLVDAS (Ensemble Stream Prediction) CLVDAS (Real Predicion) [Sawada and Koike, JGR-A, submitted] Ecosystem damage of the Horn of Africa drought is predictable 10 months before.
Area Index timeseries CLVDAS (Ensemble Stream Prediction) CLVDAS (Real Predicion) Gray: Climatorogy Green: Horn of Africa drought (reanalysis) [Sawada and Koike, JGR-A, submitted]
Area Index timeseries CLVDAS (Ensemble Stream Prediction) CLVDAS (Real Predicion) Gray: Climatorogy Green: Horn of Africa drought (reanalysis) [Sawada and Koike, JGR-A, submitted]
Area Index timeseries CLVDAS (Ensemble Stream Prediction) CLVDAS (Real Predicion) Gray: Climatorogy Green: Horn of Africa drought (reanalysis) [Sawada and Koike, JGR-A, submitted] Ensemble stream prediction (with no meteorological prediction skill) can predict ecosystem damages to some extent in the short lead time predictions.
to hydrological deficits, we can get the holistic view of severe drought progress. • We make it possible to monitor and predict droughts in the data scarce regions by using the globally applicable satellite data and data assimilation technology. Towards early-warning system of mega-droughts in the data scarce regions by integrating numerical simulation and satellite observations.