scholarly journals A New Method to Produce Sea Surface Temperature Using Satellite Data Assimilation into an Atmosphere–Ocean Mixed Layer Coupled Model

2013 ◽  
Vol 30 (12) ◽  
pp. 2926-2943 ◽  
Author(s):  
Eunjeong Lee ◽  
Yign Noh ◽  
Naoki Hirose
Keyword(s):  
Data Assimilation ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Mixed Layer ◽  
Satellite Data ◽  
Weather Prediction ◽  
Coupled Model ◽  
Sea Surface ◽  
New Method ◽  
Ocean Mixed Layer

Abstract A new method of producing sea surface temperature (SST) data for numerical weather prediction is suggested, which is obtained from the assimilation of satellite-derived SST into an atmosphere–ocean mixed layer coupled model. The Weather Research and Forecasting (WRF) Model and the Noh mixed layer model are used for the atmosphere and ocean mixed layer models, respectively. Data assimilation (DA) is carried out in two steps, based on the estimation from the covariance matching method that the daily mean SST of satellite data is more accurate than the model data, if the number of data in a grid per day is sufficiently large—that is, the daily mean SST bias correction in the first DA and the sequential SST anomaly correction in the second DA. For the second DA, the model restarts from the initial condition corrected by the first DA, and DA is applied every 30 min using the nudging method. The daily mean and the diurnal variation of satellite SST are assimilated to the bulk and skin SST, respectively. The modeled results with the new data assimilation scheme are validated by statistical comparison with independent satellite and buoy data such as correlation coefficient, root-mean-square difference, and bias. Furthermore, the sensitivity and seasonal variation of the weighting factor in the second DA are examined. The new approach illustrates the possibility of applying the atmosphere–ocean mixed layer coupled model for the production of SST data combined with the assimilation of satellite data.

On the Ocean Mixed Layer influence on the genesis of Mediterranean Tropical-Like cyclones

2020 ◽  
Author(s):  
Antonio Ricchi ◽  
Davide Bonaldo ◽  
Mario Marcello Miglietta ◽  
Sandro Carniel
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Case Studies ◽  
Mixed Layer ◽  
Heat Content ◽  
Heat Fluxes ◽  
Ocean Heat Content ◽  
Sea Surface ◽  
Lapse Rate ◽  
Ocean Mixed Layer

<p>The Mediterranean basin is the formation site of a vast number and type of cyclones. Among these, we can occasionally identify intense vortices showing tropical characteristics, called Tropical-Like Cyclones (TLC) or MEDIcanes (Mediterranean Hurricane). Their development has been studied in several case studies, showing the influence of synoptic scale upper level forcings and mesoscale features, such as the sea surface temperature and the characteristics of the air masses on the formation area. The importance of Sea Surface Temperature (SST) consists in modulating the intense latent and sensible heat fluxes, which control the development of the TLC. For tropical cyclones, one of the most studied factors in recent years is the ocean heat content in the formation basin of these storms. We plan here to extend this analysis to TLC. Besides innovative studies with coupled atmosphere-waves-ocean numerical models, a simpler approach for investigating the sole effect of the ocean heat content consists of adopting a simplified ocean (1-Dimensional) description by varying the local characteristics of the Ocean Mixed Layer (OML). In this work we use the WRF (Weather Research and Forecasting system) model, in standalone (atmospheric) mode, with 3 km grid spacing, forced with GFS-GDAL (0.25°x0.25° horizontal resolution) and SST initialization provided by the MFS-CMEMs Copernicus dataset. Three case studies of TLC are examined here, namely ROLF (06-09/11/2011), ILONA (19-21/01/2014) and NUMA (11-20/11/2017). The ocean is simulated with an OML approach, with SST updated at each iteration as a function of the atmospheric heat fluxes and with an average mixed layer deph (MDL) provided by the MFS-CMEMS dataset. For each TLC studied, the MDL is modified by increasing and decreasing its depth by 50% and increasing and decreasing its lapse rate by 50%. The results show how the structure of the MDL influences not only the intensity of the cyclone but also the structure and precipitation both in terms of quantity and location. These outcomes suggest that, as for hurricanes, also for MEDICANES the heat content of the mass of seawater plays a fundamental role in their intensification, suggesting further studies also in a climate change perspective.</p>

scholarly journals Upper-Ocean Mixed Layer and Wintertime Sea Surface Temperature Anomalies in the North Pacific

2006 ◽  
Vol 19 (2) ◽  
pp. 300-307 ◽  
Author(s):  
Tomohiko Tomita ◽  
Masami Nonaka
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Mixed Layer ◽  
North Pacific ◽  
Sea Surface ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
The North ◽  
The Impact ◽  
The North Pacific

Abstract In the North Pacific, the wintertime sea surface temperature anomaly (SSTA), which is represented by March (SSTAMar), when the upper-ocean mixed layer depth (hMar) reaches its maximum, is formed by the anomalous surface forcing from fall to winter (S′). As a parameter of volume, hMar has a potential to modify the impact of S′ on SSTAMar. Introducing an upper-ocean heat budget equation, the present study identifies the physical relationship among the spatial distributions of hMar, S′, and SSTAMar. The long-term mean of hMar adjusts the spatial distribution of SSTAMar. Without the adjustment, the impact of S′ on SSTAMar is overestimated where the hMar mean is deep. Since hMar is partially due to seawater temperature, it leads to nonlinearity between the S′ and the SSTAMar. When the SSTAMar is negative (positive), the sensitivity to S′ is impervious (responsive) with the deepening (shoaling) of the hMar compared to the linear sensitivity. The thermal impacts from the ocean to the atmosphere might be underestimated under the assumption of the linear relationship.

scholarly journals On the Ocean Mixed Layer influence on the genesis of Mediterranean Tropical-Like cyclones

2021 ◽  
Author(s):  
Antonio Ricchi ◽  
Giovanni Liguori ◽  
Leone Cavicchia ◽  
Mario Marcello Miglietta ◽  
Davide Bonaldo ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Case Studies ◽  
Mixed Layer ◽  
Heat Content ◽  
Heat Fluxes ◽  
Ocean Heat Content ◽  
Sea Surface ◽  
Ocean Mixed Layer ◽  
Vast Number

<p>The Mediterranean basin is the formation site of a vast number and type of cyclones. Among these, we can occasionally identify intense vortices showing tropical characteristics, called Tropical-Like Cyclones (TLC). Their development has been studied in several case studies, showing the influence of synoptic scale upper level forcings and mesoscale features, such as the sea surface temperature and the characteristics of the air masses on the formation area. The importance of Sea Surface Temperature (SST) consists in modulating the intense latent and sensible heat fluxes, which control the development of the TLC. For tropical cyclones, one of the most studied factors in recent years is the ocean heat content in the formation basin of these storms. We plan here to extend this analysis to TLC. Besides innovative studies with coupled atmosphere-waves-ocean numerical models, a simpler approach for investigating the sole effect of the ocean heat content consists of adopting a simplified ocean description by varying the local characteristics of the Ocean Mixed Layer (OML). In this work we use the WRF (Weather Research and Forecasting system) model, in standalone (atmospheric) mode, with 3 km grid spacing, forced with GFS-GDAL (0.25°x0.25° horizontal resolution) and SST initialization provided by the MFS-CMEMs Copernicus dataset. Two case studies of TLC are examined here, namely ROLF (06-09/11/2011) and IANOS (14-19/09/2020). The ocean is simulated with an OML approach, with SST updated at each iteration as a function of the atmospheric heat fluxes and with an average mixed layer deph (MDL) provided by the MFS-CMEMS dataset. For each TLC studied, the MDL is modified by increasing and decreasing its depth by 10 mt, 30 mt, 50 mt . The preliminary results show how the structure of the MDL influences  the intensity of the cyclone but also the structure and precipitation both in terms of quantity and location. </p>

Assimilation of Satellite Sea Surface Temperature Retrievals

2003 ◽  
Vol 84 (11) ◽  
pp. 1575-1580 ◽  
Author(s):  
Andrew Harris ◽  
Eileen Maturi
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Satellite Data ◽  
Weather Prediction ◽  
Information Service ◽  
Sea Surface ◽  
Science Center ◽  
Optimal Method ◽  
External Data ◽  
The Impact

The Workshop on Assimilation of Satellite Sea Surface Temperatures (SST) Retrievals was held on 24–26 April 2001 in Camp Springs, Maryland, at the National Oceanic and Atmospheric Administration (NOAA) Science Center. The purpose of the workshop was for NOAA's National Environmental Satellite Data and Information Service Office of Research and Applications to initiate a collaborative project with the U.S. Navy, National Centers for Environmental Prediction, the industry, and academia. The concept of the project was to develop an optimal method for assimilating satellite data into operational analyses of sea surface temperature. The aim of the workshop was to develop a demonstration system with the following results. First, ensure that the advantages of each data type (polar orbiting and geostationary) are fully exploited, while minimizing the impact of potential errors. Second, employ state-of-the-art radiative transfer modeling, variational assimilation techniques, intersensor calibration, and use of external data such as upper-air temperatures and humidities. The resulting product will represent the next big step in use of satellite data for sea surface temperature and should be the product of choice for numerical weather prediction, operational oceanography, and fisheries and climate research.

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