Assessing the stability of US High Plains land-cover: integration of process modeling with Landsat, in situ modern and paleoclimatic data

Robert Webb
Climate Diagnostics Center

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Abstract

The U.S. High Plains stretching from Idaho to Minnesota southward through New Mexico and Texas, Within the range of the instrumental record, the 1950's and 1930's droughts stand out as regional hydroclimatic extremes with significant economic and environmental impacts. Paleoenvironmental data for the Great Plains indicate that these hydroclimatic extremes and the resulting eolian land-cover change were significantly larger than during the era extensive land-use of the 20th Century. Drought induced change is the largest threat to land-cover on the over 100,000 km2 of stabilized eolian (wind-generated) deposits of the High-Plains, a fact made even more clear by the paleoclimatic observation that much bigger land-cover change took place prior to significant human land-use change of the last few centruies. Although climatic change, and to an equal extent human land-use, has caused small areas of the High Plains eolian deposits (e.g., sand dunes and sand sheets) to mobilize during the 20th Century, the paleoclimatic record indicates much greater amounts of wind-generated eolian land-cover change took place during the last 10,000 years of interglacial climate. Since this climate regime was not dramatically unlike that of this century, it is possible that a future shift in climate forcing could have a profound impact of the natural and agricultural land-cover presently stabilizing the over 100,000 km2 of "paleo" eolian deposits. For this reason, it is key that we the underlying mechanisms of climate change and variability that resulted in the paleoenvironmental record of Holocene hydrologic extremes in central North America.

Our project has used an interdisciplinary effort involving remotely-sensed data, field-based paleoclimate analyses, and process modeling to enhance current understanding of the sensitivity of High Plains land-cover to climate and human land-use forcing. The remote sensing component is focused on using Landsat images to digitally map changes land-cover in response to hydroclimatic extremes (wet and dry conditions), thus monitoring land-use and land-cover change and understanding the rates of land-cover change in the face of different climatic and human land-use forcing. The paleoclimate component has been designed to obtain precise documentation on the spatial coherence of specific dune reactivation intervals across the High Plains while providing better temporal control on the latest Holocene dune reactivation, and a possible early to middle Holocene peak in aridity. The process modeling component was devised to constrain the range of possible types of land-cover change under specified climate and land-use forcing; an approach designed to assess why High Plains land-cover changed in the past and how it may change seasons, years or decades in the future.

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19 Apr, 2000
3:30 PM/ DSRC 1D 403
(Coffee at 3:20 PM)
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