(+1.71E-02)(+0.88E-02)(+0.29E-02)(+0.09E-02)

Introduction of the Global Hydrological Simulation System using GSMaP

References[1] Takata, K., S. Emori, and T. Watanabe, 2003: Development of the Minimal Advanced Treatments of Surface Interaction and RunOff (MATSIRO), Global and Planetary Change, vol.38, pp.209-222. [2] Yamazaki, D., S. Kanae, H. Kim, and T. Oki, 2010: A physically-based description of floodplain inundation dynamics in a global river routing model, Water Resour. Res. 47, W04501, doi:10.1029/2010WR009726.[3] Yoshimura, K., T. Sakimura, T. Oki, S. Kanae, and S. Seto, 2008: Toward flood risk prediction: a statistical approach using a 29-year river discharge simulation over Japan, Hydro. Res. Letters, vol.2, pp.22-26, doi:10.3178/HRL.2.22

Kosuke Yamamoto 1・Takeshi Hibino 2・Kei Yoshimura 2・Riko Oki1・Misako Kachi1

1Ea r th O bs e r vat i o n Re s e a rc h C e nte r ( EO RC ) , J a p a n Ae ro s p a c e E x p l o rat i o n Age n c y ( JAX A)2 I n st i tu te o f I n d u st r i a l S c i e n c e , U n i ve rs i ty o f To kyo

Introduction

System Overview

Long-term Trend

Summary & Conclusion

Experiment Spatial Resol. Temporal Resol. Period Latency Forcing

JRA55 ver.0.5-deg(Land)

0.25-deg(River)3hourly,

daily, monthly1958-present

About3.5days

Surface meteorological parameters by JRA55

MODIS ver. 〃 〃 2002-present About 5daysSame as JRA55 ver. except

solar radiation from MODIS

GSMaP ver. 〃 〃 2000-presentAbout 20days

Same as JRA55 ver. except rainfall from GSMaP

Now OPEN !! http://www.eorc.jaxa.jp/theme/water/

• Though GSMaP offers relatively small amount of precipitation compared to JRA55, increasing trends of high percentile precipitation in tropics are well reproduced (bold letter in the left fig. shows statistically significant regression coefficient).

• MODIS radiation works to suppress net evapotranspiration.

• Runoff rate of GSMaP ver. is higher than the rests. This may be due to the large spatial & temporal variability of satellite products compared to the reanalysis datasets.

TE W

g [m

/m]

SPL3SMAP soil moisture [cm3/cm3]

R=0.60RMSE=0.13MAE=0.09

R=0.61RMSE=0.14MAE=0.10

R=0.61RMSE=0.15MAE=0.11

• Global hydrological simulation system named “Today’s Earth (TE)” has been developed and its accuracy for several essential output variables is tested by using in-situ and satellite observation data.

• Need to confirm and improve runoff generation process in the model to make it adapt the realistic spatial & temporal variability of the precipitation suggested by GSMaP.

• Further analysis on seasonality and regionality of accuracy is required for actual use of the system.

(c)GSMaP(a)JRA55 (b)MODIS

The land water cycle is a key element of the climate system representing all water exchange processes at the surface. For better understanding, JAXA has developed the global land simulation system named “Today’s Earth (TE)” under the joint research with the University of Tokyo. The TE system aims to :✓ produce and evaluate long-term land water cycle dataset based on satellite observation and reanalysis data✓ contribute the society as a part of the climate services by calculating risk indices of water hazards, particularly floods

This study introduces TE system and shows its overall validation and long-term trends.

JMA 55-year Reanalysis& Satellite Obs.

Forcing Land Surface Model(MATSIRO5)

River Routing Model(CaMa-Flood)

Hydrological Variables& Risk Indices

Validation

Validation

R=0.52RMSE=3780MAE=3060Bias=-589

R=0.50RMSE=6330MAE=5160Bias=1570

R=0.54RMSE=3730MAE=3000Bias=-200

■TE-Japan• As regional version of TE, “TE-

Japan” system (spatial resol. : 1km) is now under development.

• Hindcast of 2018 Japan floods were done and the authors confirmed that the system precisely reproduced the inundated area compared to the aerial photograph information.

GSMaP precip. at 0:00(JST) July 7th, 2018

Inundation area[m2] by TE-Japan

Inundation area estimatedbased on the areal photo by GSI

Photo by YOMIURI online

※In-situ data from The Global Runoff Data Center

ii) Evap.i) Precip.

iii) Runoff

i) Precip.

(+8.00E-02)(+6.90E-02)(+2.70E-02)(+0.60E-02)

ii) Evap.

iii) Runoff

JRA55 ver. MODIS ver. GSMaP ver.

Precip.(land) 800.3 (800.3) 743.4

Evap. 647.9 633.9 548.2

Runoff 102.0 108.0 108.9

Unit : mm y-1

(Zo

nal

mea

n o

f 3

0S-

30

N)

JRA55 ver. GSMaP ver.