Evaluation of ECOSTRESS Thermal Data over South Florida Estuaries.

Jing Shi,Chuanmin Hu

doi:10.3390/s21134341

Abstract

Operational coarse-resolution satellite thermal sensors designed for global oceans are often insufficient for evaluating surface temperature of small water bodies. Here, the quality of the thermal data, collected by the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS), over several South Florida estuaries, Chesapeake Bay, and Lake Okeechobee is evaluated using both in situ and Moderate Resolution Imaging Spectroradiometer (MODIS) Sea Surface Temperature (SST) data. Overall, for SST between ~6 and ~32 °C, ECOSTRESS LST (Land Surface Temperature, used as a surrogate for SST in this study) appears to be slightly underestimated, with the underestimation being more severe at night (−1.13 °C) than during the day (−0.64 °C), in spring and summer (−1.25 ± 1.39 °C) than in autumn and winter (−0.57 ± 0.98 °C), and after May 2019 when two of the five bands failed. The root-mean-square uncertainties of ECOSTRESS SST are generally within 1–2 °C. Spatial analysis further suggests that ECOSTRESS SST covers waters closer to shore and reveals more spatial features than MODIS, with comparable image noise. From these observations, after proper georeferencing and empirical correction of the negative bias, ECOSTRESS SST may be used to evaluate the thermal environments of small water bodies, thus filling gaps in the coarse-resolution satellite data.

Highlights

Over the past decade, many estuaries in South Florida have been under ecological stress with frequent and recurrent algal blooms and seagrass mortalities, such as cyanobacterial blooms and brown tide blooms in Caloosahatchee River Estuary (CRE) [1,2] and in Florida Bay (FB) [3]
The objective of this study is to evaluate ECOSTRESS surface temperature data collected over South Florida estuaries using in situ measurements and well-calibrated and validated Moderate Resolution Imaging Spectroradiometer (MODIS) measurements whenever resolution is not an issue
The negative bias and

Summary

Introduction

Many estuaries in South Florida have been under ecological stress with frequent and recurrent algal blooms and seagrass mortalities, such as cyanobacterial blooms and brown tide blooms in Caloosahatchee River Estuary (CRE) [1,2] and in Florida Bay (FB) [3]. Thermal stress has been reported, such as the 2010 cold event [4] Corresponding to these abnormal events, fish kills, seagrass die-offs, coral mortality, and lobster die-offs have been reported [4,5,6,7]. In order to have such an assessment, a long-term, consistent, temperature record for each estuary needs to be established first, through measurements of sea surface temperature (SST). In this context, following the convention, SST refers to water surface temperature regardless of whether the water is seawater or freshwater

Objectives

Results

Conclusion