| Figure 4. Estimates of snow water equivalent. Researchers are improving the accuracy of models to better estimate total snow water equivalent over a broad area. The examples below show how estimates of snow water equivalent can vary depending on the approach used. In the first approach (a), researchers use remotely sensed images to estimate the snow-covered area (SCA), expressed as a percent of SCA in each image pixel. In the second example (b), SNOTEL snow water equivalent (SWE) data, collected at point locations, are interpolated to estimate SWE over the entire region. Researchers correct estimates of snow water equivalent, by combining information about SCA (a) and interpolated SWE (b) and by manually removing the influence of cloud cover and sun reflectance from remotely sensed images. The final product (c) shows accurate area snow water equivalent estimates for the entire region, which the researchers can then provide to planners, farmers, and resource managers. The fourth image (d) shows the location of the Colorado River Basins. |
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