Project Funding: 2008 - 2010

NRA: 2006 NASA: EOS   

Funded by NASA

Abstract:
Vegetation and hydrological dynamics are strongly linked, particularly semi-arid zones where annual precipitation and productivity strongly correlate, and where variability is high compared to other ecosystems. We will merge data from the MODIS and QuikSCAT (microwave) records, 2000-present, with river discharge data, runoff fields, and water balance modeling for semi-arid lands to develop a comprehensive, geospatial picture of the seasonal and interannual variability in land-surface vegetation and water dynamics. These data sets provide complementary descriptions of a single earth system process; connecting them will yield a more robust and useful understanding of variability and it impacts on land surfaces processes, and thus of stresses on ecosystems and local populations that depend on them. Our recent work has shown that QuikSCAT backscatter has strong growing season interannual variability across the North American Great Plains that corresponds to variability in vegetation productivity and seasonal precipitation. We will generate a similar spatio-temporal hydrological picture through the integration of river gage time series and river network topology with water balance models over the same domain. We will identify anomalously dry and wet years in the precipitation record, quantify the size of the hydrological anomaly observed in river discharge data, quantify the magnitude and nature of anomalies observed in remote sensing data, evaluate vegetation productivity data where available (e.g., hay production data from agricultural statistics), and determine a drought-threshold signal (combined extent and magnitude) in the merged optical/infrared and microwave remote sensing data that corresponds to significantly reduced discharge and to significantly reduced productivity. The synthesis of several independent data sets will provide a more comprehensive view of weather-driven variability in land surface and vegetation dynamics than from any individual data set. Coherence and correlation in these completely independent, spatially-distributed time series data sets will increase the confidence with which interpretations can be made.

Publications:

Albergel, C., de Rosnay, P., Gruhier, C., Munoz-Sabater, J., Hasenauer, S., Isaksen, L., Kerr, Y., Wagner, W. 2012. Evaluation of remotely sensed and modelled soil moisture products using global ground-based in situ observations. Remote Sensing of Environment. 118, 215-226. DOI: 10.1016/j.rse.2011.11.017

Frolking, S., Hagen, S., Milliman, T., Palace, M., Shimbo, J. Z., Fahnestock, M. 2012. Detection of Large-Scale Forest Canopy Change in Pan-Tropical Humid Forests 2000-2009 With the SeaWinds Ku-Band Scatterometer. IEEE Transactions on Geoscience and Remote Sensing. 50(7), 2603-2617. DOI: 10.1109/TGRS.2011.2182516

Frolking, S., Milliman, T., Seto, K. C., Friedl, M. A. 2013. A global fingerprint of macro-scale changes in urban structure from 1999 to 2009. Environmental Research Letters. 8(2), 024004. DOI: 10.1088/1748-9326/8/2/024004

Paget, A. C., Frolking, S., Long, D. G., Milliman, T. 2015. Satellite radar anisotropy observed in urban areas. International Journal of Remote Sensing. 36(2), 665-679. DOI: 10.1080/01431161.2014.999883

Salisbury, J., Vandemark, D., Campbell, J., Hunt, C., Wisser, D., Reul, N., Chapron, B. 2011. Spatial and temporal coherence between Amazon River discharge, salinity, and light absorption by colored organic carbon in western tropical Atlantic surface waters. Journal of Geophysical Research: Oceans. 116(C7). DOI: 10.1029/2011JC006989

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Detection of forest canopy change in pan-tropical humid forests 2000-2009 with the SeaWinds Ku-band scatterometer   --   (Steve Frolking, Stephen Hagen, Thomas Milliman, Michael Palace, Julia Shimbo, Mark Fahnestock)   [abstract]

2010 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• Amazonian drought – does the SeaWinds scatterometer active microwave data contain a signal?   --   (Tom Milliman, Steve Frolking, Mark Fahnestock)   [abstract]   [poster]

2008 NASA Carbon Cycle & Ecosystems Joint Science Workshop Posters

• Vegetation Phenology Assessment Using Satellite Radar Remote Sensing: Global Monitoring of Daily and Seasonal Changes in Canopy Structure and Water Status.   --   (Kyle C. McDonald, John S. Kimball, Steve Frolking, Mark Fahnestock, Thomas Milliman)   [abstract]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile