global flood and drought prediction
DESCRIPTION
Global Flood and Drought Prediction. GEWEX 2005 Meeting, June 20-24 Role of Modeling in Predictability and Prediction Studies Nathalie Voisin, Dennis P. Lettenmaier, Eric F. Wood. Global Floods and Droughts. Floods $50-60 billion USD /year, worldwide - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/1.jpg)
Global Flood and Drought Prediction
GEWEX 2005 Meeting, June 20-24
Role of Modeling in Predictability and Prediction Studies
Nathalie Voisin, Dennis P. Lettenmaier, Eric F. Wood
![Page 2: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/2.jpg)
Global Floods and Droughts
• Floods– $50-60 billion USD /year, worldwide– 520+ million people impacted per year worldwide – Estimates of up to 25,000 annual deaths
Mostly in developing countries; Mozambique in 2000 and 2001, Vietnam and others (Mekong) in 2000.
• Droughts– 1988 US Drought: $40 billion– Famine in many countries: 200,000 people killed in
Ethiopia in 1973-74
Source: United Nations University, http://update.unu.edu/archive/issue32_2.htmhttp://www.unu.edu/env/govern/ElNIno/CountryReports/inside/ethopia/Executive%20Summary/Executive%20Summary-txt.html1988 drought: NCDC : http://lwf.ncdc.noaa.gov/oa/reports/billionz.html
![Page 3: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/3.jpg)
New technologies
In the last 25 years:• Climate models• Hydrological models • Land surface schemes• Remote sensing devices • Archives, storage
Despite all these advances, no capability for performing global hydrological prediction
![Page 4: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/4.jpg)
But discontinuity on a global scale…
– Uneven observations– local hydrological models
Hydrologic warnings tend to be localized
![Page 5: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/5.jpg)
Objectives
Develop a global flood and drought nowcast and prediction system
Using
• climate ensemble forecasts• Distributed hydrologic model VIC ( U. of
Washington, Princeton University)• Satellite remote sensing information• NCEP / ECMWF data sets
![Page 6: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/6.jpg)
Forecast System Schematic *
Satellite precipitation estimates
local scale (1/2 degree) weather inputs
soil moisturesnowpack
Hydrologic model spin up
SNOTEL
Update
streamflow, soil moisture, snow water equivalent, runoff
Month 0
1-2 years back
G-LDAS /other real-time met.
forcings for spin-up
Hydrologic forecast simulation
NOWCASTS
INITIAL STATE
AMSR-E MODISUpdate
ensemble forecasts NCEP GSM ensemble
* Similar experimental procedure as used by Wood et al (2005) West-wide seasonal hydrologic forecast system
SEASONAL FORECASTS (drought)
SHORT TERM FORECASTS (flood)
![Page 7: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/7.jpg)
Hydrologic Model Spin Up
Preliminary studies• Compare Hydrological variables as
simulated by the distributed model VIC using
– Climatology: Adam and Lettenmaier (2003) and Adam et al (2005) precipitation data sets
• gauge undercatch and orography correction • 1979-1999• Refer to A & al. later on
– Satellite precipitation estimates
![Page 8: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/8.jpg)
Satellite datasets
Choosing satellite data sets
– Availability ( near real time later on)– Time resolution (daily and less)– Spatial resolution ( ½ lat/lon degree maximum)– Spatial coverage (global)
![Page 9: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/9.jpg)
Satellite based precipitation estimates
Combined IR and PMW data sets
Spatial Domain
Spatial res.
Time res. Period available
Avail.
CMORPH (Joyce et al 2004)
Global 0.25 hourly Dec 2002- daily
PERSIANN (Sorooshian et al 2000)
50oS-50oN
0.25 6 hourly Mar 2000- 2 days
CMAP (Xie and Arkin 1996, 1997)
Global 2.5 monthly Jan 1979- 1 week
GPCP 1DD (Huffman et al 2001)
Global 1 daily Oct 1996- 3 mths
3B42RT (Huffman et al 2002)
50oS-50oN
0.25 3 hourly Feb 2002 - 6 hrs
![Page 10: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/10.jpg)
Satellite precipitation estimates
Surrogate for future near real time satellite estimates:
GPCP 1DD daily precipitation
– Huffman et al 2001– Infra-Red (TMPI) over 40oS-40oN– Recalibrated TIROS Operational Vertical Sounder (TOVS)
beyond 40oS and 40oN– Scaled to match monthly GPCP Version 2 Satellite-
Gauge precipitation estimates– 1997-present
![Page 11: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/11.jpg)
Major Basins to be simulated first
World Basins
Study basins
6 simulated basins
Mackenzie
Mississippi Mekong
Danube
CongoAmazon
![Page 12: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/12.jpg)
1997-99 Water Balance (mm)
We compare hydrologic variables as simulated by VIC driven by 1997-99:
• A & al.precipitation estimates• GPCP 1DD (Huffman et al 2001) precipitation estimates
Annual (mm) Amazon Congo Danube Mack. Mekong Missip.Precip A & al. 2378 1687 888 406 1405 947
GPCP - A & al. -526 -439 -34 -10 184 -147Runoff Adam et al 1582 532 356 157 685 397
GPCP - A & al. -550 -325 -44 -26 71 -150Evap Adam et al 792 1095 527 237 720 568
GPCP - A & al. 25 -63 15 28 107 8
![Page 13: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/13.jpg)
Monthly Water Balances 1997-99
Mackenzie
0
10
20
30
40
50
60
70
80
90
1 2 3 4 5 6 7 8 9 10 11 12Months
mm
Amazon
0
50
100
150
200
250
300
350
1 2 3 4 5 6 7 8 9 10 11 12Months
mm
Precip Clim
Precip GPCP
Runoff Clim
Runoff GPCP
Evap Clim
Evap GPCP
Danube
0
20
40
60
80
100
120
140
1 2 3 4 5 6 7 8 9 10 11 12Months
mm
Precip Clim
Precip GPCP
Runoff Clim
Runoff GPCP
Evap Clim
Evap GPCP
![Page 14: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/14.jpg)
Monthly Water Balances 1997-99
Mississippi
0
20
40
60
80
100
120
140
1 2 3 4 5 6 7 8 9 10 11 12Months
mm
Precip Clim
Precip GPCP
Runoff Clim
Runoff GPCP
Evap Clim
Evap GPCP
![Page 15: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/15.jpg)
Monthly Water Balances 1997-99
Mekong
0
50
100
150
200
250
300
1 2 3 4 5 6 7 8 9 10 11 12Months
mm
Precip Clim
Precip GPCP
Runoff Clim
Runoff GPCP
Evap Clim
Evap GPCP
![Page 16: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/16.jpg)
Monthly Water Balances 1997-99
Congo
0
50
100
150
200
250
1 2 3 4 5 6 7 8 9 10 11 12Months
mm
Precip Clim
Precip GPCP
Runoff Clim
Runoff GPCP
Evap Clim
Evap GPCP
![Page 17: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/17.jpg)
Future work
• Model Spin up – Further analysis : assess bias in simulated hydrologic
variables when using satellite precipitation estimates• Extend A & al data sets to 2004
• Use CMORPH (Joyce et al 2004)
– Use other precipitation estimates: • NCEP
• ECMWF ERA 40
– Bias adjustment of forcing data set : need 10 years of observations at least
![Page 18: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/18.jpg)
Future Work
• Data Assimilation: – use satellite soil moisture
• still experimental, • need further validation and assess the additional skill in
forecast
– Use MODIS: experimental as well
• Forecasts: – Validation with retrospective forecasts, near real time
forecasts / nowcasts– Assess predictability skills ;
• initial conditions• precipitation forecast
![Page 19: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/19.jpg)
Thank You!
Credit: Philip Wijmans/ACT-LWF Trevo, Mozambique, February 2000 , http://gbgm-umc.org/umcor/00/mozphotos.stm
![Page 20: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/20.jpg)
Amazon
![Page 21: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/21.jpg)
Mekong
![Page 22: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/22.jpg)
Congo
![Page 23: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/23.jpg)
Mackenzie
![Page 24: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/24.jpg)
Danube
![Page 25: Global Flood and Drought Prediction](https://reader035.vdocument.in/reader035/viewer/2022070418/56815a34550346895dc773db/html5/thumbnails/25.jpg)
Mississippi