Features of formation and evolution of a polar cyclone in the Barents and Kara seas in December 2020

2021 ◽  
Vol 3 ◽  
pp. 44-52
Author(s):  
E.S. Nesterov ◽  
◽  
V.D. Zhupanov ◽  
A.V. Fedorenko ◽  
◽  
...  
Keyword(s):  
Wind Speed ◽  
Data Assimilation ◽  
Kara Sea ◽  
Heat Fluxes ◽  
Sensible Heat ◽  
Global Data Assimilation System ◽  
Formation And Evolution ◽  
Data Assimilation System ◽  
Global Data ◽  
Assimilation System

Based on the GDAS (Global Data Assimilation System) information, the conditions for the formation and evolution of a polar cyclone in the Barents Sea in December 2020 are studied. The cyclone in interesting because after entering the Kara Sea, the cyclone did not weaken as usual but continued to intensify. The formation of the cyclone occurred near the ice edge under conditions of the cold Arctic air outbreak. After entering the Kara Sea, the cyclone continued to deepen, which was facilitated by latent and sensible heat fluxes in the ice-free western part of the sea. According to weather station data, when the cyclone moved further over land, the wind direction changed from mainly southern to northern, and wind speed increased significantly. There also was a sharp decrease in air temperature by 7–10 °С for three hours. Keywords: polar cyclone, global data assimilation system, wind speed, latent and sensible heat fluxes

Assessment of the Impact of Simulated Satellite Lidar Wind and Retrieved 183 GHz Water Vapor Observations on a Global Data Assimilation System

1990 ◽  
Vol 118 (12) ◽  
pp. 2513-2542 ◽  
Author(s):  
Ross N. Hoffman ◽  
Christopher Grassotti ◽  
Ronald G. Isaacs ◽  
Jean-Francois Louis ◽  
Thomas Nehrkorn ◽  
...  
Keyword(s):  
Water Vapor ◽  
Data Assimilation ◽  
Global Data Assimilation System ◽  
The Impact ◽  
Data Assimilation System ◽  
Global Data ◽  
Assimilation System

Forecast Impact of Assimilating Aircraft WVSS-II Water Vapor Mixing Ratio Observations in the Global Data Assimilation System (GDAS)

2017 ◽  
Vol 32 (4) ◽  
pp. 1603-1611 ◽  
Author(s):  
Brett T. Hoover ◽  
David A. Santek ◽  
Anne-Sophie Daloz ◽  
Yafang Zhong ◽  
Richard Dworak ◽  
...  
Keyword(s):  
Water Vapor ◽  
Data Assimilation ◽  
Positive Impact ◽  
Weather Prediction ◽  
Warm Season ◽  
Precipitation Forecast ◽  
Global Data Assimilation System ◽  
Data Assimilation System ◽  
Global Data ◽  
Assimilation System

Abstract Automated aircraft observations of wind and temperature have demonstrated positive impact on numerical weather prediction since the mid-1980s. With the advent of the Water Vapor Sensing System (WVSS-II) humidity sensor, the expanding fleet of commercial aircraft with onboard automated sensors is also capable of delivering high quality moisture observations, providing vertical profiles of moisture as aircraft ascend out of and descend into airports across the continental United States. Observations from the WVSS-II have to date only been monitored within the Global Data Assimilation System (GDAS) without being assimilated. In this study, aircraft moisture observations from the WVSS-II are assimilated into the GDAS, and their impact is assessed in the Global Forecast System (GFS). A two-season study is performed, demonstrating a statistically significant positive impact on both the moisture forecast and the precipitation forecast at short range (12–36 h) during the warm season. No statistically significant impact is observed during the cold season.

Introduction of the GSI into the NCEP Global Data Assimilation System

2009 ◽  
Vol 24 (6) ◽  
pp. 1691-1705 ◽  
Author(s):  
Daryl T. Kleist ◽  
David F. Parrish ◽  
John C. Derber ◽  
Russ Treadon ◽  
Wan-Shu Wu ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Environmental Modeling ◽  
Analysis Scheme ◽  
Global Data Assimilation System ◽  
Analysis System ◽  
Data Assimilation System ◽  
Global Data ◽  
Statistical Interpolation ◽  
New System ◽  
Assimilation System

Abstract At the National Centers for Environmental Prediction (NCEP), a new three-dimensional variational data assimilation (3DVAR) analysis system was implemented into the operational Global Data Assimilation System (GDAS) on 1 May 2007. The new analysis system, the Gridpoint Statistical Interpolation (GSI), replaced the Spectral Statistical Interpolation (SSI) 3DVAR system, which had been operational since 1991. The GSI was developed at the Environmental Modeling Center at NCEP as part of an effort to create a more unified, robust, and efficient analysis scheme. The key aspect of the GSI is that it formulates the analysis in model grid space, which allows for more flexibility in the application of the background error covariances and makes it straightforward for a single analysis system to be used across a broad range of applications, including both global and regional modeling systems and domains. Due to the constraints of working with an operational system, the final GDAS package included many changes other than just a simple replacing of the SSI with the new GSI. The new GDAS package contained an upgrade to the Global Forecast System model, including a new vertical coordinate, as well as new features in the GSI that were never developed for the SSI. Some of these new features included changes to the observation selection, quality control, minimization algorithm, dynamic balance constraint, and assimilation of new observation types. The evaluation of the new system relative to the SSI-based system was performed for nearly an entire year of analyses and forecasts. The objective and subjective evaluations showed that the new package exhibited superior forecast performance relative to the old SSI-based system. The new system has been shown to improve forecast skill in the tropics and substantially reduce the short-term forecast error in the extratropics. This implementation has laid the groundwork for future scientific advancements in data assimilation at NCEP.

The Canadian Global Data Assimilation System: Description and Evaluation

1993 ◽  
Vol 121 (5) ◽  
pp. 1467-1492 ◽  
Author(s):  
Herschel L. Mitchell ◽  
Cécilien Charette ◽  
Steven J. Lambert ◽  
Jacques Hallé ◽  
Clément Chouinard
Keyword(s):  
Data Assimilation ◽  
System Description ◽  
Global Data Assimilation System ◽  
Data Assimilation System ◽  
Global Data ◽  
Assimilation System
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