scholarly journals Nighttime Cool Skin Effect Observed from Infrared SST Autonomous Radiometer (ISAR) and Depth Temperatures

2020 ◽  
Vol 37 (1) ◽  
pp. 33-46 ◽  
Author(s):  
Haifeng Zhang ◽  
Helen Beggs ◽  
Alexander Ignatov ◽  
Alexander V. Babanin
Keyword(s):  
Heat Flux ◽  
Quality Control ◽  
Physical Model ◽  
Skin Effect ◽  
Sea Surface ◽  
Average Value ◽  
Diurnal Warming ◽  
Cool Skin ◽  
Infrared Sst ◽  
Basic Features

AbstractThe nighttime ocean cool skin signal ΔT [defined as skin sea surface temperature (SSTskin) minus depth SST (SSTdepth)] is investigated using 103 days of matchups between shipborne Infrared SST Autonomous Radiometer (ISAR) SSTskin and water intake SSTdepth at ~7.1–9.9-m depths, in oceans around Australia. Before data analysis, strict quality control of ISAR SSTskin data is conducted and possible diurnal warming contamination is carefully minimized. The statistical distribution of ΔT, and its dependencies on wind speed, heat flux, etc., are consistent with previous findings. The overall average ΔT value is −0.23 K. It is observed that the magnitude of the cool skin signal increases after midnight and a coolest skin offset (with an average value of −0.36 K) is found at around dawn. The dependency of ΔT on SST conditions is observed. Direct warm skin events are discovered when the net heat flux direction is from the atmosphere to the ocean, which is more likely to occur at high latitudes when the air is very humid and warmer than the SST. In addition, several cool skin models are validated: one widely used physical model performs best and can capture most skin-effect trends and details; the empirical models only reflect the basic features of the observed ΔT values. If the user cannot apply the physical model (due to, e.g., the algorithm complexity or missing inputs), then the empirical parameterization in the form proposed in a 2002 study can be used. However, we recommend using a new set of parameters, calculated in this study, based on much more representative dataset, and with more rigorous quality control.

Cool Skin Effect and its Impact on the Computation of the Latent Heat Flux in the South China Sea

2021 ◽  
Vol 126 (1) ◽  
Author(s):  
Rongwang Zhang ◽  
Fenghua Zhou ◽  
Xin Wang ◽  
Dongxiao Wang ◽  
Sergey K. Gulev
Keyword(s):  
Heat Flux ◽  
South China Sea ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
South China ◽  
Skin Effect ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Cool Skin

scholarly journals An empirical model for the statistics of sea surface diurnal warming

Ocean Science ◽  
2012 ◽  
Vol 8 (2) ◽  
pp. 197-209 ◽  
Author(s):  
M. J. Filipiak ◽  
C. J. Merchant ◽  
H. Kettle ◽  
P. Le Borgne
Keyword(s):  
Heat Flux ◽  
Wind Speed ◽  
Statistical Model ◽  
Surface Heat Flux ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Surface Heat ◽  
Sea Surface ◽  
Diurnal Warming ◽  
Nwp Model

Abstract. A statistical model is derived relating the diurnal variation of sea surface temperature (SST) to the net surface heat flux and surface wind speed from a numerical weather prediction (NWP) model. The model is derived using fluxes and winds from the European Centre for Medium-Range Weather Forecasting (ECMWF) NWP model and SSTs from the Spinning Enhanced Visible and Infrared Imager (SEVIRI). In the model, diurnal warming has a linear dependence on the net surface heat flux integrated since (approximately) dawn and an inverse quadratic dependence on the maximum of the surface wind speed in the same period. The model coefficients are found by matching, for a given integrated heat flux, the frequency distributions of the maximum wind speed and the observed warming. Diurnal cooling, where it occurs, is modelled as proportional to the integrated heat flux divided by the heat capacity of the seasonal mixed layer. The model reproduces the statistics (mean, standard deviation, and 95-percentile) of the diurnal variation of SST seen by SEVIRI and reproduces the geographical pattern of mean warming seen by the Advanced Microwave Scanning Radiometer (AMSR-E). We use the functional dependencies in the statistical model to test the behaviour of two physical model of diurnal warming that display contrasting systematic errors.

scholarly journals A statistical model for sea surface diurnal warming driven by numerical weather prediction fluxes and winds

2010 ◽  
Vol 7 (4) ◽  
pp. 1497-1532 ◽  
Author(s):  
M. J. Filipiak ◽  
C. J. Merchant ◽  
H. Kettle ◽  
P. Le Borgne
Keyword(s):  
Heat Flux ◽  
Wind Speed ◽  
Statistical Model ◽  
Weather Prediction ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Surface Heat ◽  
Sea Surface ◽  
Diurnal Warming ◽  
Nwp Model

Abstract. A statistical model is derived relating the diurnal variation of sea surface temperature (SST) to the net surface heat flux and surface wind speed from a numerical weather prediction (NWP) model. The model is derived using fluxes and winds from the European Centre for Medium-Range Weather Forecasting (ECMWF) NWP model and SSTs from the Spinning Enhanced Visible and Infrared Imager (SEVIRI). In the model, diurnal warming has a linear dependence on the net surface heat flux integrated since (approximately) dawn and an inverse quadratic dependence on the maximum of the surface wind speed in the same period. The model coefficients are found by matching, for a given integrated heat flux, the frequency distributions of the maximum wind speed deceedance and the observed warming exceedance. Diurnal cooling, where it occurs, is modelled as proportional to the integrated heat efflux divided by the heat capacity of the seasonal mixed layer. The model reproduces the statistics (mean, standard deviation, and 95-percentile) of the diurnal variation of SST seen by SEVIRI and reproduces the geographical pattern of mean warming seen by the Advanced Microwave Scanning Radiometer (AMSR-E). We use the functional dependencies in the statistical model to test the behaviour of two physical model of diurnal warming that display contrasting systematic errors.

scholarly journals Comparison of Himawari-8 AHI SST with Shipboard Skin SST Measurements in the Australian Region

2020 ◽  
Vol 12 (8) ◽  
pp. 1237 ◽  
Author(s):  
Minglun Yang ◽  
Lei Guan ◽  
Helen Beggs ◽  
Nicole Morgan ◽  
Yukio Kurihara ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Sea Surface ◽  
High Temporal Resolution ◽  
Diurnal Warming ◽  
Australian Region ◽  
Maximum Value ◽  
Infrared Sst ◽  
The Mean

Sea surface temperature (SST) measurements from the geostationary satellite Himawari-8 Advanced Himawari Imager (AHI) are compared with in situ skin SSTs derived from shipboard Infrared SST Autonomous Radiometers (ISAR) in the Australian region. The mean bias and standard deviation of the differences between Himawari-8 AHI and ISAR skin SST of best quality are 0.09 K and 0.30 K, with total matchups numbering 2701. Shipboard bulk SST measurements at depths between around 7.1 and 9.9 meters are compared with the matchups in a case study. Analyses show significant differences between skin and bulk SST measurements of maximum value 2.23 K under conditions of high diurnal warming. The results also demonstrate that Himawari-8 AHI skin SST with high temporal resolution has the ability to accurately measure diurnal warming events.

Variational assimilation of observation data in the mathematical model of the Baltic Sea dynamics

2015 ◽  
Vol 30 (4) ◽  
Author(s):  
Valeriy I. Agoshkov ◽  
Eugene I. Parmuzin ◽  
Vladimir B. Zalesny ◽  
Victor P. Shutyaev ◽  
Natalia B. Zakharova ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Heat Flux ◽  
Baltic Sea ◽  
Satellite Observation ◽  
Sea Surface ◽  
Observation Data ◽  
The Baltic Sea ◽  
Variational Assimilation ◽  
The Baltic ◽  
The Mathematical Model

AbstractA mathematical model of the dynamics of the Baltic Sea is considered. A problem of variational assimilation of sea surface temperature (SST) data is formulated and studied. Based on variational assimilation of satellite observation data, an algorithm solving the inverse problem of heat flux restoration on the interface of two media is proposed. The results of numerical experiments reconstructing the heat flux functions in the problem of variational assimilation of SST observation data are presented. The influence of SST assimilation on other hydrodynamic parameters of the model is considered.

scholarly journals The thermal structure of Israel

2011 ◽  
Vol 3 (1) ◽  
pp. 431-452 ◽  
Author(s):  
E. Shalev ◽  
V. Lyakhovsky ◽  
Y. Weinstein ◽  
Z. Ben-Avraham
Keyword(s):  
Heat Flux ◽  
Thermal Structure ◽  
Local Heating ◽  
Arabian Shield ◽  
Supporting Evidence ◽  
Hydrologic Models ◽  
Average Value ◽  
Water Wells ◽  
Shear Heating ◽  
Deep Seismicity

Abstract. Heat flux at the Arabian Shield is a significant component in reconstructing tectonic, seismic, and hydrologic models. In this paper we analyze temperature data from all the available oil and water wells in Israel. We show that the average heat flux in Israel is 40–45 mW m−2. A supporting evidence for the low heat flux is the relatively deep seismicity, extending almost to the mantle in the region. A Heat flux anomaly that exists in Northern Israel and Jordan could be attributed to groundwater flow or young magmatic activity (~100 000 years) that is common in this area. Xenoliths that yield relatively steep geothermal gradients could be the result of local heating by magmas or by lithospheric necking and shear heating. The higher Heat flux in Southern Israel and Jordan probably reflects the opening of the Red Sea and the Gulf of Eilat and does not reflect the average value of the Arabian Shield.

Design and Calibration of a Novel High Temperature Heat Flux Gage

2005 ◽  
Author(s):  
Sujay Raphael-Mabel ◽  
Scott Huxtable ◽  
Andrew Gifford ◽  
Thomas E. Diller
Keyword(s):  
Heat Flux ◽  
High Temperature ◽  
High Heat ◽  
Heat Flux Sensor ◽  
High Heat Flux ◽  
Average Value ◽  
Metal Plates ◽  
New Type ◽  
Flux Sensor ◽  
Calibration Apparatus

A new type of heat flux sensor (HTHFS) has been designed and constructed for applications at high temperature and high heat flux. It is constructed by connecting solid metal plates to form brass/steel thermocouple junctions in a series circuit. The thermal resistance layer of the HTHFS consists of the thermocouple materials themselves, thus improving temperature limits and lowering the temperature disruption of the sensor. The sensor can even withstand considerable erosion of the surface with little effect on the operation. A new type of convection calibration apparatus was designed and built specifically to supply a large convection heat flux. The heat flux was supplied simultaneously to both a test and standard gage by using two heated jets of air that impinged perpendicularly on the surface of each gage. The sensitivity for the HTHFS was measured to have an average value of 20 μV/(W/cm2). The uncertainty in this result was determined to be ±10% over the entire range tested. The sensitivity agrees with the theoretically calculated sensitivity for the materials and geometry used. Recommendations for future improvements in the construction and use of the sensors are discussed.

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