availability of eps products on internet and gts - WMO

... charts from a number of sources and EPS modelling centres, could then form
the basis for case studies and even real time exercises. ... Direct display on
workstation, possibly using a Java page to allow looping etc. Web friendly
formats, e.g. png, gif ... [5] http://www.wmo.ch/web/www/DPS/Global-Producers/
Doc5-10.pdf.

Part of the document


|WORLD METEOROLOGICAL ORGANIZATION | |CBS ET/EPS/Doc. 4(1) |
|_________________ | | |
| | |(18.VIII.2003) |
|COMMISSION FOR BASIC SYSTEMS | |_______ |
|OPAG ON DPFS | | |
| | | |
|EXPERT TEAM ON | |Item: 4 |
|ENSEMBLE PREDICTION SYSTEMS | | |
| | |Original: ENGLISH |
|Geneva, Switzerland, 27-31 October 2003 | | |





AVAILABILITY OF EPS PRODUCTS ON
INTERNET AND GTS


(Submitted by Tony Simmers, Meteorological Service of New Zealand)


____________________________________________________

Summary and purpose of document


The available ensemble prediction system products are reviewed and
some recommendations are proposed.



_____________________________________________________


Action proposed


The expert team is invited to take into account the information given
in this document.



Introduction

1. At the core of both the benefits and costs of ensemble prediction
systems is an increase of one to two orders of magnitude in the amount of
data the forecasts are based on. Getting ensemble data to forecast
providers, particularly those from less well-resourced countries poses a
number of challenges. Discussion in this paper concentrates on EPS products
targeted at the medium to early extended range, and on data appropriate for
forecasters to use in an operational setting.


Availability of Ensemble Data

2. The previous meeting of the ET/EPS produced a list of products that
were recommended for routine distribution. The list of products, together
with a collection of links to web sites with images, can be found on a web
site hosted by WMO[1].

3. The number of products available through links on the website is
evidence that a considerable, and growing, amount of information is freely
available on the web. For seasonal forecasts many of the sites offer
global coverage, however for medium range forecasts most of the sites cater
only for their domestic region of interest. NCEP and ECMWF however have
made particular efforts to advertise the availability of global data from
their medium range ensembles. New Zealand gratefully acknowledges using
data from both these centres for its domestic forecasting. Encouraging
producers of EPS products to release global data would extend the choices
available to countries that are not located in the immediate geographical
area of a modelling centre.

4. Of the types of product recommended for routine distribution by the
previous meeting of the ET/EPS, the most commonly found on web sites are
plots of ensemble mean and standard deviation; and probabilities of
precipitation and wind speed. Vector winds, temperature anomalies, and
storm tracks do not seem to feature as prominently. The likely reasons for
this are a combination of the effort required to make each product, and the
demand for them.

5. Overall, while more sites are offering products, the variety of
forecasts from ensemble systems does not seem to have increased greatly
over the last few years. What is noticeable however, is an increased range
of verification measures, including those associated with economic value.
Together these factors point to a 'coming of age;' for ensemble forecasts,
where the emphasis is shifting from how to make and access the data onto
how to best use the forecasts.

6. Currently nearly all transfer of EPS data occurs across the Internet
as opposed to the GTS. While this works well for countries that have
access to high speed connections, the volumes of data even for a set of
basic charts (