Search NASA⌕ Search

SEARCH · Search NASA

Results for “Geostationary”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

Quantifying Burned Area of Wildfires in the Western United States From Polar-Orbiting and Geostationary Satellite Active-Fire Detections

Background : Accurately estimating burned area from satellites is key to improving biomass burning emission models, studying fire evolution and assessing environmental impact. Previous studies have found that current methods for estimating burned area of fires from satellite active-fire data do not always provide an accurate estimate. Aims and Methods : In this work, we develop a novel algorithm to estimate hourly accumulated burned area based on the area from boundaries of non-convex polygons containing the accumulated Visible Infrared Imaging Radiometer Suite (VIIRS)active-fire detections. Hourly time series are created by combining VIIRS estimates with fire radiative power (FRP) estimates from GOES-17 data. Conclusions, Key Results and Implication : We evaluate the performance of the algorithm for both accumulated and change in burned area between airborne observations, and specifically examine sensitivity to the choice of the parameter controlling how much the boundary can shrink towards the interior of the area polygon. Results of the hourly accumulation of burned area for multiple fires from 2019 and 2020 generally correlate strongly with airborne infrared (IR) observations collected by the United States Forest Service National Infrared Operations (NIROPS), exhibiting correlation coefficient values usually greater than 0.95 and errors <20%.

burned area↗
NASA NTRSDate not supplied

Additional Characterization of Sonoran Pics in Support of A Stable Multi-Sensor Geostationary Imager Record

The Sonoran Desert is the most utilized Pseudo Invariant Calibration Site (PICS) located in the Americas for post-launch radiometer drift monitoring and sensor pair radiometric scaling. The Sonoran Desert is located near the US Arizona and Mexican border with an elevation of 37 m. The site has small spatial and angular variations; however, soil moisture can cause short- term periodic reflectance fluctuations. The NASA Clouds and the Earth’s Radiant Energy System (CERES) project utilizes the site to validate the GOES East and West imager calibration coefficients derived from inter-calibrating GOES with MODIS. Because the daily local noon angular solar and viewing angles repeat every year over the site, a daily exoatmospheric radiance model (DERM) can be constructed over the lifetime of a well-calibrated GOES sensor. DERM based on a well-calibrated GOES imager can then be used to determine the calibration coefficients of successive GOES imagers to provide a stable multi-sensor GOES imager record. This will ensure that the GOES retrieved clouds and derived broadband fluxes can be used to infer the regional diurnal cycle in between Terra and Aqua CERES measurements to accurately compute the daily mean regional fluxes and clouds over the 20-year CERES SYN1deg product. Although the Sonoran Desert surface reflectance and atmospheric column vary seasonally, the inter-annual variability of the seasonal cycle is small, but it adds noise to the resulting DERM calibration coefficients. We seek to reduce the uncertainty of the DERM approach by improving the clear-sky filtering and correlating the observed interannual reflectance variability with atmospheric parameters, such as precipitable water, ozone concentration, and aerosol optical depth. The additional characterization of the Sonoran Desert site DERM for both the GOES East and West positions should improve the accuracy of the CERES SYN1deg product clouds and fluxes.

Prathana Khakurel↗