As new observation systems are developed and deployed, new and presumably more precise information is becoming available for weather forecasting and climate monitoring. To take advantage of these new observations, it is desirable to have schemes to accurately retrieve the information before statistical analyses are performed so that statistical computation can be more effectively used where it ...

As there are few in situ observations in and around Antarctica, it is important to assess how assimilating remotely-sensed observations, such as satellite-observed radiances, can fill this observational gap. Thus, a month-long study was conducted over the Antarctic to examine forecast and analysis sensitivity to the assimilation of microwave radiance measurements. Several experiments were confi...

Impact of GPS (Global Positioning System) data assimilation is assessed here using a high-resolution numerical weather prediction system at 2.5 km horizontal resolution. The Zenithal Tropospheric Delay (ZTD) GPS data from mesoscale networks are assimilated with the 3DVAR AROME data assimilation scheme. Data from more than 280 stations over the model domain have been assimilated during 15-day lo...

The impact of global positioning system (GPS) radio occultation (RO) data on an intense synoptic-scale storm that occurred over the Southern Ocean in December 2007 is evaluated, and a synoptic explanation of the assessed impact is offered. The impact is assessed by using the three-dimensional variational data assimilation scheme (3DVAR) of the Weather Research and Forecasting (WRF) Model Data A...

Because of the ongoing climate change, frequency extreme rainfall events at global scale is expected to increase, resulting in higher social and economic impacts. Thus, improving forecast accuracy risk communication a fundamental goal limit damages. Both Numerical Weather Prediction (NWP) radar-based nowcasting systems still have open issues, mainly terms precipitation correct time/space locali...

[1] With the advent of the Global Positioning System (GPS) measurements (from both ground-based and satellite-based receivers), the number of available ionospheric measurements has dramatically increased. Total electron content (TEC) measurements from GPS instruments augment observations from more traditional ionospheric instruments like ionospheric sounders and Langmuir probes. This volume of ...

The present paper aims to provide a brief review on several deterministic ensemble Kalman filtering (EnKF) methods and the related practical techniques to prevent filter divergence. Since Evensen (1994), several formulations of EnKF have been proposed, and Whitaker and Hamill (2002) suggested that a deterministic method, a.k.a. an ensemble square root filter (EnSRF, Andrews 1968), is expected t...

In this paper, a new method of dual-Doppler radar wind analysis based on a three-dimensional variational data assimilation (3DVAR) approach is proposed. In it, a cost function, including background term and radial observation term, is minimized through a limited memory, quasi-Newton conjugate-gradient algorithm with the mass continuity equation imposed as a weak constraint. In the method, the b...

A Japanese long-term reanalysis (JRA-25) was completed in 2006 utilizing the comprehensive set of observations from the 40-yr ECMWF Re-Analysis (ERA-40). JRA-25 and ERA-40 adopted the same type of assimilation systems: 3DVAR with direct use of satellite sounding radiances. Long-term upper-air thermal tendencies in both reanalyses are examined and compared with the observational deep-layer tempe...

A high-resolution simulation of the 8 May 2003 Oklahoma tornadic supercell is analyzed to determine the origin of internal outflow surges within the low-level cold pool. The analyzed simulation has 50-m horizontal grid spacing and is quadruply nested within larger, lower-resolution domains that were initialized via threedimensional variational data assimilation (3DVAR) of radar and other observ...