An Approach to Estimate the Water Level and Volume of Dongting Lake by using Terra/MODIS Data

Size: px

Start display at page:

Download "An Approach to Estimate the Water Level and Volume of Dongting Lake by using Terra/MODIS Data"

Margery Lee
6 years ago
Views:

National Institute for Environmental Studies, Japan An Approach to Estimate the Water Level and Volume of Dongting Lake by using Terra/MODIS Data 2002 Jan. Feb. Mar. Apr.

1 National Institute for Environmental Studies, Japan An Approach to Estimate the Water Level and Volume of Dongting Lake by using Terra/MODIS Data 2002 Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Volume ( 10 8 m 3 ) Total 2002 Month 2002 Satoshi KAMEYAMA, Jiqun ZHANG, Qinxue WANG, Kaiqin XU, Takao KATOH and Masataka WATANABE

soil run off by excess development in upper region (Xu et al. (2000c)). 2.

2 Introduction 1. Recently Changjiang middle region (from Yichang to Hankou in main stream) faces a serious cumulative effect of soil run off by excess development in upper region (Xu et al. (2000c)). 2. There are many disasters that concern frequent flooding or over flows in Dongting Lake region. To resolve of these problem, the monitoring of Dongting lake in long term (or through the year ) and its technology development are urgent need in China recently.

3 Application of Remote Sensing Winter (minimum season) Flooded (Maxim season) 1-16,Jan (Julian day:001) 27,Jun.-11,Jul (Julian day:177) MODIS Image (MOD13,R:G:B=6:5:4) surrounding Donting Lake region. Background data are landuse map in 1km mesh.

4 Objectives The multiple roles of Large lakes and wetland have a new understanding. (Retention for floods, Water purification, Convention on Biological Diversity etc.) To detect the flooded area in Dongting Lake using remote sensing data (Terra/MODIS NDVI data) To estimate the water level and storage volume of Dongting Lake based on the two methods. 2-1 Actual water level data and GIS DEM data. 2-2 MODIS image and GIS DEM data. Through these study, we ll develop the technology that monitor the spacio-temporal change of flooded area and water volume in large lake( Dongting Lake) or wetland.

5 Study area Chenglingji St. EDL: East Dongting Lake China WDL SDL R:G:B=8:5:7 MOD13 Date:2002/11/01~16 Xiaohe St. Yingtian St km The satellite (Terra/MODIS) image of test site (Dong ting Lake) and the location. The band combination for MODIS MOD13 is R=8,G=5,B=7. The green region in the image is inside of the lake.

6 Flowchart of the Study MODIS data ( MOD13:NDVI, 22 scene in 2002) Method1 Data1 Data2 Elevation of water surface in Chenglingji St.(EDL) Result1 Result2 Threshold value (Water surface vs. Terrestrial area ) Result3 5:flooded area Extraction of the lake s edge pixel Elevation of the Lake s edge (water level of three lakes.) Method2 8:Water storage Data3 6: Water level in Yingtian St (SDL) and Xiaohe St (WDL) Result4 The regression curve water level vs. storage volume Result5 DEM (50m mesh) 8:Water storage

7 DATA 1 Terra/MODIS MOD 13data list that used in this analysis. Because of the data from 04/23 to 05/08 included many noise in the image we omitted the data in this study. DATE Julian day Spatial resolution (m) DATE Julian day Spatial resolution (m) 2002/01/01-01/ /07/12-07/ /17 02/ /28 08/ /02 02/ /13 08/ /18 03/ /29 09/ /06 03/ /14 09/ /22 04/ /30 10/ /07 04/ /16 10/ /23 05/ /01 11/ /09 05/ /17 12/ /25 06/ /03 12/ /10 06/ /19 12/ /26 07/11 177

8 DATA 2 Elevation of water surface (m) (a.s.l.) m 16 days period of MODIS DATA Julian day in 2002 The annual change of water surface elevation in Chenglingji St.(EDL)

DATA 3 Elevation of lake bottom a.s.l.(m) 0-20 20-22 22-24 24-26 26-28 28-30 30-32 32-34 34-36 36-38 38-40 The three polygons DL The virtual measurement line Lat.

9 DATA 3 Elevation of lake bottom a.s.l.(m) The three polygons DL The virtual measurement line Lat. 29q20 N SDL EDL Chenglingji water level monitoring St. Xiaohe St. Yingtian St. The DEM of Dongting Lake bottom and tree polygons divided from whole Dongting Lake. The special resolution of DEM is 50m 50m Chinese Academy of Sciences (Nanjing geology research institute)

10 Method 1 Decision of threshold between water surface and terrestrial area MODIS NDVI Threshold value Elevation NDVI values of Lake s edge pixels Measured water level The virtual measurement line Lat. 29q20 N EDL Chenglingji water level monitoring St. a.s.l.(m) DL SDL

Method 2 1. Detect the elevation values from the edge pixels of extracted flooded area. The regression curve Calculation of water storage from two data. 3.

11 Method 2 1. Detect the elevation values from the edge pixels of extracted flooded area. The regression curve Calculation of water storage from two data. 3.use the relationship between water level and water strage based on DEM Water level =Elevation-DEM 2. Calculate the water surface elevation from the mean of detected elevation surface elevation Water Storage (m 3 ) Water Level (m) MODIS Image Station. data

12 Result 1 NDVI values of Lake s edge pixels MODIS MOD13 NDVI value Elevation of lake bottom (m) Actual Measured data (in Chenglingji St.) Scatter diagram elevation of lake bottom vs. MOD13 NDVI value ( 129 in Julian day)

Result 2 0 50 km Jan. Feb. Mar. Apr. May Jun. Jul. Aug. 2002 Sep. Oct. Nov. Dec.

13 Result km Jan. Feb. Mar. Apr. May Jun. Jul. Aug Sep. Oct. Nov. Dec. The annual distribute patterns of Dongting Lake flooded area based on MODIS image. The dark blue color region shows the detected water surface area.

14 Result 3 EDL SDL WDL Water level (m) MODIS data Measured in Chenglingji St. Jan. Mar. May Jul. Sep. Nov. Yingtian St. Jan. Mar. May Jul. Sep. Nov. Month Xiaohe St. Jan. Mar. May Jul. Sep. Nov. The comparison of water level between measured data in each St. and estimated data based on MODIS image in three lakes in ( ): measured data in each local Station ( ): estimated data based on MODIS image analysis.

15 Result 4 Water storage volume (m 3 ) The regression curve between water level and water volume in each lake based on DEM \ [ [ [ [ [Z Z Z Z Annual change of water level in [Z Z Z Z Water level (m) EDL SDL WDL The 2nd APEIS Capacity Building Workshop, (November 24-29, Sydney, Australia)

16 Result EDL SDL WDL GIS DEM data Volume (m 3 ) MODIS data Jan. Mar. May Jul. Sep. Nov. Jan. Mar. May Jul. Sep. Nov. Month Jan. Mar. May Jul. Sep. Nov. The Comparison of water volume between measured data and estimated data based on MODIS image in three lakes in ( ): measured data in each Station, ( ): estimated volume based on MODIS image analysis.

17 Result Total 10 8 y = x x x x R 2 = 1 Volume (m 3 ) GIS DEM Volume (m 3 ) MODIS data Jan. Mar. May Jul. Sep. Nov. Nov. Month Water level in Chenglingji (m) Annual change of water volume in total Dongting Lake in The relationship between water level in Chenglingji St. and water volume of whole Dongting Lake.

18 Conclusion. We detect the water flooded area of Dongting Lake form Terra/MODIS image (16days NDVI) based on NDVI threshold value through the year Annual change of water level and water storage volume was calculated combining DEM data and detected flooded area using GIS. 3. The trend of spacio-temporal change of flooded area and water volume of Dongting Lake was that the maximum of water level and volume were estimated in June m 8 3 and August m 8 3, on the other hand the minimum was showed from December to March ( m 8 3 ) through the year For flood monitoring of large lake. The remote sensing application to estimate water level and volume using MODIS data is very effective in terms of time and cost saving.

GAMINGRE 8/1/ of 7

GAMINGRE 8/1/ of 7 FYE 09/30/92 JULY 92 0.00 254,550.00 0.00 0 0 0 0 0 0 0 0 0 254,550.00 0.00 0.00 0.00 0.00 254,550.00 AUG 10,616,710.31 5,299.95 845,656.83 84,565.68 61,084.86 23,480.82 339,734.73 135,893.89 67,946.95