• 葉面積指標(LAI) • Total Water Storage データ同化で求めたいものの例 • モデルの未知パラメータ [Moradkhani et al. 2005 AWR; Yang et al. 2009 JHM; Verbeeck et al. 2011 JGR; Sawada and Koike 2014 JGR; Bacour et al. 2015 JGR] • 根茎層土壌水分 [Kumar et al. 2009 JHM; Tran et al. 2014 WRR; Sawada et al. 2015 JGR] • フラックス [Jarlan et al. 2008 JGR; Martens et al. 2017 GMD] etc…
Parameter Optimization 3. Particle Filter 2.1. CLVDAS Coupled Land and Vegetation Data Assimilation System (CLVDAS) Meteorological forcings [Sawada and Koike 2014 JGR-A] [Sawada et al. 2015 JGR-A] Land Surface Model Radiative Transfer Model in microwave region Rain, radiation,….. Soil moisture, vegetation water content,….. Simulated Microwave brightness temperature Satellite Observed Microwave brightness temperature Soil moisture, LAI, parameter
Parameter Optimization 3. Particle Filter 2.2. 陸面モデル EcoHydro-SiB Coupled Land and Vegetation Data Assimilation System (CLVDAS) Meteorological forcings [Sawada and Koike 2014 JGR-A] [Sawada et al. 2015 JGR-A] Land Surface Model Radiative Transfer Model in microwave region Rain, radiation,….. Soil moisture, vegetation water content,….. Simulated Microwave brightness temperature Satellite Observed Microwave brightness temperature Soil moisture, LAI, parameter transpiration rainfall intercept evaporation soil moisture transfer ground water photosynthesis growth runoff EcoHydro-SiB [Sawada et al. 2014 WRR] Vegetation dynamics is explicitly solved.
Parameter Optimization 3. Particle Filter 2.3. 放射伝達モデル Coupled Land and Vegetation Data Assimilation System (CLVDAS) Meteorological forcings [Sawada and Koike 2014 JGR-A] [Sawada et al. 2015 JGR-A] Land Surface Model Radiative Transfer Model in microwave region Rain, radiation,….. Soil moisture, vegetation water content,….. Simulated Microwave brightness temperature Satellite Observed Microwave brightness temperature Soil moisture, LAI, parameter RTM [Kuria et al. 2007 IEEE TGARS; Sawada et al. 2017 RS] Radiation from soil Surface Soil Moisture Attenuation by canopy Radiation from canopy Vegetation water content Microwave brightness temperature is sensitive to both surface soil moisture and vegetation water content.
Parameter Optimization 3. Particle Filter 2.4.1. データ同化その1 -モデルパラメータ感度解析- Coupled Land and Vegetation Data Assimilation System (CLVDAS) Meteorological forcings [Sawada and Koike 2014 JGR-A] [Sawada et al. 2015 JGR-A] Land Surface Model Radiative Transfer Model in microwave region Rain, radiation,….. Soil moisture, vegetation water content,….. Simulated Microwave brightness temperature Satellite Observed Microwave brightness temperature Soil moisture, LAI, parameter j i k j i n ijk ij i i Y V V V V V .... 12 ....... パラメータの変化によって生じる出力の変化全体 を個別のパラメータの寄与に分解する。大域的な パラメータの感度が求まることが特徴 [Saltelli et al. 2010 Comp. Phys. Comm.] Global Sensitivity Analysis 上式の分散を大量のアンサンブル計算で近似 するため、非常に多くのパラメータの組み合わ せでモデルを時間積分する必要がある。。
Parameter Optimization 3. Particle Filter 2.5.1. データ同化その2 -モデルパラメータ最適化- Coupled Land and Vegetation Data Assimilation System (CLVDAS) Meteorological forcings [Sawada and Koike 2014 JGR-A] [Sawada et al. 2015 JGR-A] Land Surface Model Radiative Transfer Model in microwave region Rain, radiation,….. Soil moisture, vegetation water content,….. Simulated Microwave brightness temperature Satellite Observed Microwave brightness temperature Soil moisture, LAI, parameter Shuffled Complex Evolution [Duan et al. 1992 WRR] による最適化 パラメータ モデルを1年くらい計算 推定輝度温度 観測輝度温度 コスト関数 モデル推定と観測の差が十分小さくなるまで モデルの長期積分を繰り返す。
Parameter Optimization 3. Particle Filter 2.6.1. データ同化その3 -粒子フィルタによる逐次同化- Coupled Land and Vegetation Data Assimilation System (CLVDAS) Meteorological forcings [Sawada and Koike 2014 JGR-A] [Sawada et al. 2015 JGR-A] Land Surface Model Radiative Transfer Model in microwave region Rain, radiation,….. Soil moisture, vegetation water content,….. Simulated Microwave brightness temperature Satellite Observed Microwave brightness temperature Soil moisture, LAI, parameter Model obs × × × × Selection & Resample Mutation Model T = 1 LAIとすべての層の土壌水分を観測を 同化して5日おきに補正する 低LAI, 低RSM 高LAI, 高RSM RSM: Root-zone soil moisture 各粒子がすべてのモデルの状態量を保持する ことで、直接観測されない量も補正できる。
ECoHydrological Land Analysis(ECHLA) Meteorological forcings Land Surface Model Radiative Transfer Model in microwave region Rain, radiation,….. Soil moisture, vegetation water content,….. Simulated Microwave brightness temperature Satellite Observed Microwave brightness temperature Soil moisture, LAI Meteorological Forcings: GLDAS Microwave observation: AMSR-E Period: 2003-2011/9 Study Area: Global snow-free region 現状ではパラメータ推定は省略 (計算コスト低減のため)