3D Weather Research Articles

Low-Frequency Variability in a GCM: Three-Dimensional Flow Regimes and Their Dynamics

Abstract General circulation models (GCMs) can be used to develop diagnostics for identifying weather regimes. The author has looked for three-dimensional (3D) weather regimes associated with a 10-yr run of the U.K. UGAMP GCM with perpetual January boundary conditions; 3D low-pass empirical orthogonal functions (EOFs), using both the 500- and 250-mb streamfunctions (ψ) have been computed. These EOFs provide a low-order phase space in which weather regimes are studied. The technique here is an extension to 3D of that of Haines and Hannachi. They found, within the 500-mb ψ EOF phase space, two local minima of area-averaged ψ-tendency (based on barotropic vorticity dynamics), which were identified as ±Pacific–North America (PNA). In this work, the author demands that both the flow and its tendency be within the phase space spanned by the 3D EOFs. The streamfunction tendency is computed from the two-level quasigeostrophic potential vorticity equation and projected onto the EOF phase space. This projection pro...

First results with a parallelized 3D weather prediction code

A survey on the parallelization of the 2D model of the Integrated Forecasting System (IFS), the weather prediction code of the ECMWF, is given in this issue [4]. In this short note, we present first results of the parallelization of the corresponding 3D version.

AOIPS/2: An interactive system to process, analyze, and display meteorological data sets for nowcasting

The Atmospheric and Oceanographic Information Processing System 2 (AOIPS/2) is a high performance interactive meteorological processing system where many meteorological data ingest, processing, analysis and display functions may be performed. These functions may be carried out on many types of meteorological data including those from satellites, radars, rawinsondes, surface observations, as well as special aircraft instruments and 3D numerical weather model simulations. Presently the capability to ingest real-time conventional data is being enhanced, and work is in progress to directly receive satellite and radar data. The AOIPS/2 capability to integrate these real-time data makes it an effective tool for nowcasting experiments. The AOIPS/2 hardware system consists of several 32 bit super microcomputers networked to a larger general purpose computer. Two of the “super micros” serve as hosts to commercially available image terminals while two others act as hosts to satellite and conventional data ingest systems. When the AOIPS/2 system was designed the following improvements over previous systems were sought: 1) integration of all the major software packages used by the Severe Storms Branch into the METPAK software system, 2) use of microcomputers which could be located near the users, 3) use of a distributed system to eliminate interference of CPU intensive image processing function with other users, and 4) minimization of the work involved in future upgrades to new computers or image terminals. The basic specifications and features of the AOIPS/2 include: 1) a distributed system of MicroVAX IIs, linked by Ethernet to a VAX 780 running VMS based software, 2) two International Imaging System (IIS) 75 image terminals with advanced hardware features like shift, zoom, and histogram etc. on dedicated MicroVAX II host computers eliminating interference between users 3) the Transportable Applications Executive (TAE), user interface and the Display Management System (DMS), an image terminal independent software sub-system developed at GSFC 4) METPAK, an extensive software package which includes satellite (VISSR and VAS), radar, and aircraft data processing, analysis and display functions, 5) GEMPAK which processes conventional data as well as the output products from METPAK (Note: all software is written according to modern software standards of modularity, comments, etc.) 6) real-time GOES satellite data ingest and enhanced conventional data ingest are under development at the present time. The whole system is located in the scientists work area with access to local high resolution large screen video projection for seminars and demonstrations. Products and results using the AOIPS/2 are presented to illustrate the capabilities of the systems.