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Tropospheric Polar Vortices and Impacts on Atmospheric Flow from the Arctic to the Mid-Latitudes using a New Global Modeling System
(2020-05-08)
The observed rapid changes in the Arctic are important to quantify not only for understanding the region, but also for understanding how processes between the Arctic and lower latitudes can interact to culminate in high-impact ...
Improving short-term forecast of severe and high-impact weather events using a weather-dependent hybrid ensemble-variational data assimilation system with radar and satellite derived observations
(2023-05-12)
A hybrid ensemble-variational (EnVAR) data assimilation and forecast system, namely WoF-Hybrid, was initially developed at the National Severe Storms Laboratory (NSSL) supported by the NOAA Warn-on-Forecast project (WoF). ...
FOUR-DIMENSIONAL ENSEMBLE KALMAN FILTER ASSIMILATION OF HIGH TEMPORAL RESOLUTION PHASED ARRAY RADAR DATA WITH REAL CONVECTIVE STORM CASES
(2020-05)
With the US National Weather Service (NWS) Weather Surveillance Radar-1988 Doppler (WSR-88D) radar network aging, a candidate for replacing it is phased array radar (PAR). The defining feature of PAR is an electronically ...
Improving High-Resolution Tropical Cyclone Prediction using a Cycled, GSI-Based Hybrid Ensemble-Variational Data Assimilation System for HWRF with Vortex Scale Observations
(2019-12-13)
A Gridpoint Statistical Interpolation analysis system (GSI)-based, continuously cycled, dual-resolution hybrid ensemble-variational (EnVar) data assimilation (DA) system is developed for the Hurricane Weather Research and ...
A Comparison of Hybrid-4DEnVar and Hourly Hybrid-3DEnVar Assimilation of Tail Doppler Radar Observations on the Prediction of Rapidly Evolving Hurricanes
(2019-08-01)
Beginning in the summer of 2017 the National Weather Service upgraded the operational Hurricane WRF (HWRF) to a continuously cycled Gridpoint Statistical Interpolation (GSI) based, 6-hourly, Hybrid 3-dimensional (3D) ...
A Comparative Convective Study Between the Ensemble Kalman Filter and the Local Particle Filter Using the Gridpoint Statistical Interpolation System
(2020-07-30)
The localized particle filter (LPF) is a recent advance in ensemble data assimilation for numerical weather prediction. Derived from the original particle filter used for highly nonlinear state variables, the LPF incorporates ...
TEST OF DIFFERENT TRANSFORMATION FUNCTIONS TO HYDROMETEOR AND WATER VAPOR MIXING RATIOS FOR DIRECT VARIATIONAL ASSIMILATION OF RADAR REFLECTIVITY DATA
(2021-05-14)
Many issues exist when using highly nonlinear radar reflectivity forward observation operator in three-dimensional variational data assimilation methods (3DVAR), especially with hydrometeor mixing ratios as control variables ...
Impact of Assimilating Ground-Based and Airborne Radar Observations for the Analysis and Prediction of the Eyewall Replacement Cycle of Hurricane Matthew (2016) Using HWRF Hybrid 3DEnVar System
(2021-08-05)
Eyewall replacement cycles (ERC) are common dynamical processes in mature tropical cyclones (TCs) that can result in quick changes to the storm’s intensity and wind field size. As the resolution of TC models increases, ...
Impact of data assimilation and model physics on the predictability of the 2012 Great Arctic Cyclone
(2022-08-04)
Impact of data assimilation and model physics on the predictability of the 2012 Great Arctic Cyclone
A case study of the Great Arctic Cyclone 2012 (AC12) is used to understand the role of initial condition errors and model ...