Analysis of hydrological spatial and temporal characteristic scales over
the Contiguous United States using GOES-16 Land Surface Temperature
retrievals
Abstract
Land surface features such as elevation, soils, land use, and vegetation
fluctuate on scales ranging from millimeters to hundreds of kilometers.
The state of the land surface and many hydrological processes vary
accordingly. Land surface temperature (LST) is a crucial factor
determining the interactions between the land surface and the atmosphere
(i.e., energy, water, and carbon fluxes). Decades of global satellite
remote sensed LST fields are now available, constituting an
unprecedented opportunity to understand better the factors influencing
hydrological variability from regional to global scales. An important
under-researched aspect regarding variability, at least over continental
extents, is determining the scales for which hydrological variations are
spatially and temporally related. These scales would serve as indicators
for the required time and spatial resolution for observational systems.
This presentation will address this gap in understanding across scales
through a comprehensive analysis of spatial and temporal correlation
lengths of LST across the contiguous United States (CONUS). Correlation
lengths (CLs) are measures of the stationarity of a property
distribution both in space and time. They reveal the scales of
variability for fields thus, contributing to estimating the stationarity
of the property. Temporal correlation lengths (tCLs) express the
property changes in time for a fixed location, providing a measure of
the persistence or variability of the time series. On the other hand,
spatial correlation lengths (sCLs) depict the spatial patterns of the
property over a predefined area by representing the distance for which
variations are spatially related. As part of our evaluation, we will
analyze derived fields of tCLs and sCLs for the ~2x2
km2 GOES-16 LST hourly product over CONUS. A
0.25-degree regular grid over CONUS will be defined, and an hourly time
step between 2017 and 2021 will be used for the analysis. The obtained
CLs will be assessed in terms of the time of the day and season.
Additionally, we propose a comparison of well-known spatiotemporal
influencing factors of LST such as land cover, surface thermal
properties, topography, incoming solar radiation, and meteorological
conditions.