Estimation of monthly mean air-sea temperature difference from satellite observations using genetic algorithm

Abstract Infrared scintillation measurements were obtained along a 7-km path over San Diego Bay concurrently with meteorological measurements obtained from a buoy at the midpoint of the path. Bulk estimates of the refractive index structure parameter were computed from the buoy data and compared with scintillation-derived values. The bulk estimates agreed well with the scintillation measurements in unstable conditions. In stable conditions the bulk estimates became increasingly higher than the scintillation values as the air–sea temperature difference increased. This disagreement may be due to enhanced wave-induced mixing of the lower atmosphere that decreases the vertical temperature and humidity gradients in stable conditions from the assumed Monin–Obukhov similarity (MOS) theory forms, resulting in bulk values that are too high. The bulk estimates decrease rapidly when the absolute air–sea temperature difference approaches small positive values. These predicted decreases in were not observed in either the path-averaged scintillation measurements or in single-point turbulence measurements, indicating that bulk models for estimating scalar structure parameters based on mean air–sea scalar differences are not valid when the mean air–sea difference approaches zero. The authors believe that the most promising means toward improving the bulk model is to obtain a better understanding of the MOS functions over the ocean for a wide stability range, and particularly of the role of ocean waves in modifying near-surface vertical gradients and turbulence characteristics.

Download Full-text

Correction to “Sensitivity of satellite multichannel sea surface temperature retrievals to the air-sea temperature difference” by Douglas A. May and Ronald J. Holyer

Journal of Geophysical Research Atmospheres ◽

10.1029/93jc02077 ◽

1993 ◽

Vol 98 (C11) ◽

pp. 20337

Author(s):

Douglas A. May ◽

Ronald J. Holyer

Keyword(s):

Surface Temperature ◽

Sea Surface Temperature ◽

Temperature Difference ◽

Sea Surface ◽

Sea Temperature

Download Full-text

On Thermal Infrared Remote Sensing of Plastic Pollution in Natural Waters

Remote Sensing ◽

10.3390/rs11182159 ◽

2019 ◽

Vol 11 (18) ◽

pp. 2159 ◽

Cited By ~ 6

Author(s):

Lonneke Goddijn-Murphy ◽

Benjamin Williamson

Keyword(s):

Remote Sensing ◽

Temperature Difference ◽

Natural Waters ◽

Thermal Infrared ◽

Short Wave ◽

Plastic Pollution ◽

Thermal Infrared Remote Sensing ◽

Sea Temperature ◽

Weather Forecasts ◽

Surface Fraction

Plastic pollution in the world’s natural waters is of growing concern and currently receiving significant attention. However, remote sensing of marine plastic litter is still in the developmental stage. Most progress has been made in spectral remote sensing using visible to short-wave infrared wavelengths where optical physics applies. Thermal infrared (TIR) sensing could potentially monitor plastic water pollution but has not been studied in detail. We applied radiative transfer theory to predict TIR sensitivity to changes in the surface fraction of water covered by plastic litter and found that the temperature difference between the water surface and the surroundings controls the TIR signal. Hence, we mapped this difference for various months and times of the day using global SST (sea surface temperature) and t2m (temperature at 2 m height) hourly estimates from the European Centre for Medium-Range Weather Forecasts (ECMWF), ERA5. The maps show how SST-t2m difference varied, altering the anticipated effectivity of TIR floating plastic litter remote sensing. We selected several locations of interest to predict the effectivity of TIR sensing of the plastic surface fraction. TIR remote sensing has promising potential and is expected to be more effective in areas with a high air–sea temperature difference.

Download Full-text