Tag: qingyuan zhang

Figure. Two images showing the same geographical area. (Left) VIIRS 375-m daily floodwater extent product on 4 July 2025, with the locations of the Guadalupe River and the towns of Ingram and Kerrville superimposed. Cloudy conditions were in place so no flood inundation information was available, hence the gray background. (Right) The SAR flood inundation map on 4 July 2025, showing some flooded areas (in red).

Mapping the Extent of the Devastating July 4 Texas Flash Flood Event

July 14, 2025

The July 2025 flood event in Texas Hill Country, fueled by remnants of Tropical Storm Barry, resulted in, to date, 135 fatalities, including 28 children

Figure: Influence of lemming herbivory on vegetation: (A) monthly fAPARchl in July and August during 2001 – 2014; (B) difference of monthly fAPARchl between August and July during 2001 – 2014; and (C) relative variations of August VGCF, SOILCF, and fAPARchl to year 2008 in format (Varix ⁄Vari2008 -1) ×100% where Vari = VGCF, SOILCF, and fAPARchl, and x=2007 – 2014.

Abiotic and Biotic Factors Impacting Tundra Productivity in Alaska

October 10, 2023

ESSIC/CISESS Scientist Qingyuan Zhang has published a paper entitled “Impacts of abiotic and biotic factors on tundra productivity near Utqiaġvik, Alaska” in Environmental Research Letters.

Figure 2. The RAPID-based Sentinel-1 30 m floodwater extent and depth maps for an area in California on 03/14/2023.

Monitoring California Flooding Using VIIRS and Sentinel-1

April 3, 2023

ESSIC Associate Research Scientist Qingyuan Zhang recently used VIIRS daily 375m flood extent products on 3/8/2023, 3/11/2023, 3/13/2023 and 3/15/2023 to monitor flooding in California.

Figure: The VIIRS Flood map, Sentinel-1 SAR Flood map, and the comprehensively blended Flood map on 10/2/2022 reporting flood extent due to Hurricane Ian.

Florida Flood Maps for Hurricane Ian

October 21, 2022

Hurricane Ian made landfall in Florida on the afternoon of 9/28/2022 as a massive Category 4 storm and brought record-setting winds. As of 10/4/2022, at least 105 people have been reported as casualties of Hurricane Ian, 55 of which in Lee County, Florida. Even more people are without power or their home. The NOAA STAR Flood team has produced VIIRS Flood maps, Sentinel-1 SAR Flood maps, and blended Flood maps to report the flood extent due to Hurricane Ian.

$Figure. The 6 × 6 km2 Howland forest area in Maine: (A) the true color image obtained by the EO-1 Hyperion on March 5, 2014 (DOY 64) at a spatial resolution of 30 m; and maps of (B) snow cover fraction (SNOWCF); (C) surface water cover fraction (WaterBodyCF); (D)soil cover fraction (SOILCF); (E) vegetation cover fraction (VGCF); (F) fAPARcanopy; (G) fAPARchl; (H) fAPARnon-chl.$

An Evergreen Forest Ecosystem from Satellites

November 16, 2021

ESSIC/CISESS Scientist Qingyuan Zhang has a new article to be published in International Journal of Applied Earth Observation and Geoinformation that characterizes the seasonally snow-covered Howland boreal forest ecosystem in Maine, USA with satellite images.

Figure 1. Two comparison examples of VIIRS FIM products and Sentinel-1 SAR FIM products in March during Midwestern Great Flood in 2019 (SAR FIM products are available at https://rapid-nrt-flood-maps.s3.amazonaws.com/).

Accelerating the Exploitation of Satellite Observations to Improve Flood and Inundation Monitoring and Forecasts

August 4, 2021

ESSIC/CISESS Scientist Qingyuan Zhang and their colleagues have developed a framework to compare Visible/Infrared Imager Radiometer Suite (VIIRS) Flood Inundation Maps (FIM) with Sentinel-1 synthetic aperture radar (SAR) FIM.