NASA IDS project meeting: Precipitation and LULC change datasets

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NASA IDS project meetingPrecipitation and LULC
change datasets
Hongjie Xie The University of Texas at San
Antonio
March 19, 2009 at Texas AM, Corpus Christi
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Year 1

• Downscaled the NEXRDA MPE 4 km to 1 km provided
  for Liangs group for modeling

2004-2007, totally 34,842 hourly data
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Guan, Xie, Wilson Submitted to J of Hydrology
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Year 2

• Processed NEXRAD Stage IV (2004-2007)
• Examined methods for improving NEXRDA accuracy
• Started to build the SWAT model for Guadalupe
  River Bain
• Started working on the USGS LULC change dataset

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2.1 NEXRAD Stage IV (2004-2007)

• Stage IV data of 2004-2007 has been downloaded,
  processed, aggregated into 3 hourly files, and
  provided for Liangs group.
• All 3 hourly files were provided in the NetCDF
  format

22º N to 37º N, and 100º W to 75º W
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Missing files only found in 2004
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2.2 Improving NEXRDA accuracy

• Explored four methods to improve the NEXRDA
  precipitation accuracy, by incorporating rain
  gauge measurements
• Bias Adjustment (BA)
• Simple Kriging with varying Local Means (SKlm)
• Kriging with External Drift (KED)
• Regression Kriging (RK)
• To evaluate which method is better, four
  evaluation parameters are used
• Percentage Bias,
• Mean Absolute Error,
• Coefficient of Determination,
• Nash-Sutcliffe efficiency

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Hour 9, June 22nd, 2004
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Hour 8, April 24nd, 2004
Hour 8, June 22nd, 2004
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Evaluation parameters of predicted areal mean
precipitation and precipitation at three rain
gauges for the year of 2004
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Box-and-whisker plot of the PBIAS, MAE, R2 and
NSE values of the 50 rain gauge for four
different methods
Results show that the average performance of SKlm
is similar to or better than the other three
methods. -- A paper is in submission
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2.3 SWAT model for Guadalupe River Bain

• Soil and Water Assessment Tool (SWAT)
• DEM, precipitation, temperature, land cover/land
  use and soil type as input
• Use measured water quality data to tune the
  parameters.
• nitrate (NO3), ammonium (NH4), dissolved oxygen
  (DO), total dissolved phosphorus (TDP), phosphate
  (PO4), total organic carbon (TOC), total nitrogen
  (TN) and total phosphorus (TP)
• Data are getting from the Jims group (not yet).
• Once well-tuned and calibrated, it can be used to
  estimate the water quality, which can be used to
  compare with water quality estimates, from Jims
  empirical modeling approach.

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78 stations
90 m DEM were used to delineate the basin and
subbasins 21 subbasins and 226 HRUs
(hydrological response units)
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Key Procedures

• Create SWAT project
• Delineate watershed (DEM, basin shapefile)
• Define land use/soil/slope data grids (land
  cover/land use, soil type)
• Determine the distribution of HRUs
• Define rainfall, temperature and other weather
  data
• Write the SWAT input files
• Setup and run SWAT

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Water quality calibration Using NCDC gauge
precipitation as input

• Data Source
• rainfall and temperature data 1990-2007
• Water quality data 1993 2007 (daily, monthly
  or yearly)
• Model spin-up 1990-1992
• Calibration period 1993-2007
• Calibration parameters
• nitrate (NO3), ammonium (NH4), dissolved oxygen
  (DO), total dissolved phosphorus (TDP), phosphate
  (PO4), total organic carbon (TOC), total nitrogen
  (TN) and total phosphorus (TP)

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2.4 LULC change dataset

• We examined the USGS LULCC dataset
• Landsat 1992
• Landsat 2001
• A preliminary analysis was done in Bexar county
• For new changes since 2001, we need MODIS yearly
  1 km (we can process them if any group need them)

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LULC and Change 1992-2001

• Open water
• Urban
• Barren
• Forest
• Grassland/Shrub
• Agriculture
• Wetlands
• NN. Changes

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Example of San Antonio/Bexar County
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Bexar County
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Edwards Aquifer
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Thank you
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NEXRAD precipitation products

• NCDC Level II, III
• Level II (base) data
• Reflectivity, mean radial velocity, and spectrum
  width
• 1 km x 1 degree
• 5 or 6 minutes in rain model and 10 minutes in
  clear sky mode
• Level III products (total 41)
• DPA (4.7625 km HRAP grid, hourly, but every 5 or
  6 minutes)

• RFC Stage I, II, III
• Stage I - Hourly digital precipitation (HDP), 4
  km
• Stage II - HDP merge with gauges
• Stage III (or MPE) - Mosaicked Stage II cover a
  RFC area. MPE since 2004.
• NCEP Stage IV
• Stage IV Mosaicked Stage III or MPE for the USA.