NASA Drought Project Meeting, September 30, 2008

NOAA/PSD, CIRES/CDC Presentation

Comparing Soil Moisture Gage Data with Image Data

PSD/CDC Project Team:Brant Liebmann, brant.liebmann@noaa.gov

Dave Allured, dave.allured@noaa.gov

Boulder, Colorado

Station gage data collections

AWDN: HPRCC, Nebraska soil moisture & meteorology, daily, 37 stations.

SCAN: WCC/NRCS, Western US soil moisture & meteorology, hourly, 134 stations, not used so far. Good potential, but acquisition and format problems.

USGS: NWIS, soil moisture, mostly Wisconsin, daily, 13 stations, not used so far.

Station gage data collections

2008 Progress

Correlations and autocorrelations of AWDN Nebraska soil moisture gage data. Characterize station variability in advance of comparisons with image data.

2008 Progress

2008 Progress

Correlations of variability, gage data to MODIS NDVI. NDVI fields from USGS/EROS, 8 day time steps, 2001-2006, resolution 500 meters. Gridded analysis. Compared some of 37 AWDN stations to Nebraska fields, so far.

10 cm 25 cm

* Note red circle on station location at center of each plot.

2008 Progress

• Wide area correlation appears to increase with depth

• Correlation at station pixel is unremarkable or worse

• Very preliminary study, no conclusions drawn 100 cm50 cm

2008 Progress

Correlations of variability, gage data to VegET water balance model. USGS/EROS/SAIC, soil moisture model output, point locations. Analysis for one month only, July 2006, so far.

2008 Progress - VegET Soil Moisture Correlations

Correlations of VegET soil moisture versus: Station Name Latitude Longitude sm50 sm25 sm10 precipALLIANCENORT 42.18 -102.92 0.82 0.73 0.92 0.18 ARTHUR 41.65 -101.52 -0.51 0.27 0.68 -0.02 BARTA 42.23 -99.65 0.56 0.41 0.57 -0.08 BEATRICE 40.30 -96.93 0.22 0.08 -0.66 0.30 BRUNSWICK 42.35 -97.92 0.95 0.83 0.92 0.29 CEDAR POINT 41.20 -101.63 -0.47 -0.28 0.30 0.14 CENTRALCITY 41.15 -97.97 0.48 0.52 0.51 0.43 CHAMPION 40.40 -101.72 -0.75 0.59 0.88 0.10 COZAD 40.97 -99.95 -0.58 0.53 0.77 0.23 CURTISUNSTA 40.63 -100.50 0.22 0.16 0.45 0.01 DICKENS 40.95 -100.97 0.53 0.50 0.65 0.47 ELGIN 41.93 -98.18 -0.14 0.41 0.34 0.27 GORDON 42.73 -102.17 0.16 0.28 0.97 0.35 GRANDISLAND 40.88 -98.50 0.26 0.56 0.61 0.11 GUDMUNDSENS 42.07 -101.43 0.56 0.51 0.56 -0.13 HALSEY 41.90 -100.15 0.51 0.46 0.41 -0.06HIGGINS RANC 42.83 -99.25 0.61 0.65 0.59 -0.15 INDIAN CAVE 40.28 -95.62 -0.40 -0.19 0.80 0.23 KEARNEY 40.72 -99.02 0.59 0.53 0.17 0.11 LEXINGTON 40.77 -99.73 0.06 0.45 0.69 0.28LINCOLN 82E 40.78 -96.60 -0.23 -0.08 0.86 0.25 MERNA 41.45 -99.77 0.43 -0.11 -0.40 0.12 MINDEN 40.52 -99.05 0.81 0.80 0.80 0.16MITCHELL FAR 41.93 -103.70 0.47 0.56 0.86 0.08 MONROE 41.38 -97.52 0.84 0.51 0.61 0.23NEBRASKA CIT 40.70 -95.88 -0.43 0.59 0.76 0.10 NORTHPLATTE 41.08 -100.77 0.24 0.13 0.25 0.20 ONEILL 42.47 -98.75 -0.28 0.02 0.55 -0.10 ORD 41.62 -98.93 0.86 0.86 0.76 -0.04 REDCLOUD 40.08 -98.28 -0.35 -0.14 -0.04 0.39 SCOTTSBLUFF 41.88 -103.67 0.05 0.86 0.89 0.33 SHELTON 40.73 -98.75 -0.40 -0.21 -0.04 0.46 CLAY CENTER 40.57 -98.13 -0.21 0.07 0.84 0.36 SPARKS 42.98 -100.20 0.24 0.08 0.20 0.00 SMITHFIELD 40.58 -99.67 -0.30 0.07 0.37 0.24 WESTPOINT 41.85 -96.73 0.23 0.83 0.80 0.07 YORK 40.87 -97.62 0.51 -0.26 0.12 0.17

2008 Progress - Data Translations

MODIS NDVI to NetCDF, Nebraska only, 2001-2006, resolution 500 meters.

2008 Progress - Data Translations

QuikSCAT soil moisture change to NetCDF, continental US. SMC fields from NASA/JPL, daily, January-December 2007, resolution 0.25 degrees.

Future Work - Analysis

Expand early correlation studies.

• SMC/QuikSCAT field correlations with gage data.• Investigate spatial characteristics of gage to image correlations (radius of influence, etc.)• Further time lag analysis.• Expand study area to more of continental US with station data.• Expand record lengths in analyses to available records.

Algorithm for improved soil moisture estimates at various depths for continental US.

• The estimate would be based on some combination of image data calibrated to the ground station network.• This would be based in part on the work of the HPRCC in collaboration with Eric Hunt.• Objectives: better absolute accuracy; higher field resolution; higher reporting frequency.

Future Work - Data

Expand gage data collection to augment these studies.

Potential data translation products.

• Gridded image data to NetCDF. NDVI, SMC, etc.

• Provide data translation software for collaborators.

• Consolidated data set for soil moisture gage data from multiple sources. Translate to common format for distribution and easier usage.

• Caveat: No redistribution of proprietary data.

Future Work

Feedback requested.

•Many ideas; time and resources are limited.

•What products would augment efforts of the other NASA drought participants?