Monday June 19, 2023
PhysOrg —
After years of intense drought and diminishing groundwater, California just saw its greatest year-over-year water gains in two decades, according to data from the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) satellite mission, a partnership between NASA and the German Research Centre for Geosciences (GFZ). This past winter’s bonanza of atmospheric rivers alleviated some of the water deficit that the state incurred during periods of drought over the last 10 years, which included the three driest years on record in California.
Think of the state’s Central Valley region (outlined in yellow) as a giant swimming pool: GRACE-FO measurements include all the water contained in the lakes, rivers, soil, snowpack, and underground aquifers within that region. Between October 2022 and March 2023, storms provided enough water to raise the amount of water within the “swimming pool” by about 20 inches (about 500 millimeters). That’s about twice as much as the average winter water gain since satellite-based water storage measurements began in 2002 with the first GRACE mission.
The gain in water between October 2022 and March 2023 is apparent in the maps above. Blue colors represent areas where conditions were wetter than average (relative to 2004–2010), while red colors were drier than average. The yellow line in the chart below shows the month-to-month variations in water storage for the area outlined in yellow on the maps.