November 18, 2022.

Excerpt:

>After an extremely wet October, southeast Australia continued to see heavy rainfall in November 2022. With soils already saturated and dams full, the latest storms have added to ongoing flooding across New South Wales and Victoria.

>Widespread flooding is visible in this false-color image (right) acquired on November 18, 2022, with the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.

>Water appears light to dark blue. Vegetation is green and bare land is brown. For comparison, the MODIS image from the Aqua satellite (left) shows the same area on June 28, 2022, prior to the excessive rainfall.

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>Water that seeps deep into the soil can influence groundwater levels for months. The map above depicts shallow groundwater storage in Australia from November 11–14, 2022, as measured by the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) satellites.

>The colors depict the wetness percentile; that is, how the levels of groundwater compare to long-term records (1948–2012). Blue areas have more abundant water than usual, and orange and red areas have less.

>The extent to which such rainfall affects the groundwater level varies by location and depends on a range of factors such as soil type, aquifer depth, and vegetation. Time is also a factor, as rainfall accumulations from months past can influence current groundwater levels.

NASA Earth Observatory images by Lauren Dauphin, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview and GRACE data from the National Drought Mitigation Center. Story by Kathryn Hansen.