THE CONNECTION BETWEEN THORPEX AND IPY

***CONNECTION AT INTERNATIONAL LEVEL:***

IPY is a multidisciplinary program, covering many research areas and
scales, with a global view but a focus on the polar regions. The THORPEX
program focuses on global weather prediction research. The two programs
naturally intersect: THORPEX is considered the weather prediction
component of IPY. The strong overlap is recognized at the international
level by:

1\) Selection of Michel Beland (Meteorological Service of Canada) to
co-chair both the THORPEX International Core Steering Committee and the
ICSU-WMO Joint Committee for IPY

2\) Recognition of IPY-related research as a major part of the THORPEX
program in the THORPEX International Implementation Plan (TIP, p. 52-57)

3)  The submission and acceptance of a large number of THORPEX related
    pre-proposals under the IPY program. These proposals (27 in total)
    have been clustered under the name \"Weather and climate (including
    improved forecasts), THORPEX-IPY\"

***THORPEX-IPY SCIENTIFIC HYPOTHESES:*** Some of the underlying science
hypotheses for the joint THORPEX-IPY research work are:

*HYPOTHESIS A:* The main sources of forecast uncertainty, and the major
impediments to extending weather forecasts to day 14 and short term
climate forecasts beyond week two over the Northern Hemisphere are (1)
Tropical excitation of waves from the Pacific ocean, especially from the
area of the Maritime Continent; (2) The mid-latitude flow regime over
the Pacific Ocean; and (3) The polar circulation with episodes of cross
polar flow. A major effort must be undertaken to assess the relative
importance of each of these three sources of forecast uncertainty and
the interaction among them, as well as the optimal mix of observations
required to reduce them.

*HYPOTHESIS B:* The level of predictability and forecast skill over the
Northern vs. Southern Hemispheres are influenced by (1) The nature of
the flow regimes in the polar regions (a more symmetric circumpolar
vortex with little to no cross polar flow over the Antarctic, and a less
symmetric vortex with major episodes of cross polar flow over the
Arctic); and (2) A difference in the distribution of continents and
oceans over the two hemispheres (with a much larger contrast between
land and ocean masses over the Northern Hemisphere). A major effort must
be undertaken to describe the relationship between these two factors,
and to assess their relative roles in supporting and limiting
atmospheric predictability over different regions of the globe (polar,
mid-latitude, tropical), and the global circulation in general.

***CONNECTION AT US LEVEL:***

One of the 27 THORPEX-IPY pre-proposal submissions was prepared by Dr.
David Parsons (US co-chair of North American THORPEX Regional
Committee), on behalf of a group of NSF related scientists. D. Parsons,
with the help of a group of scientists, including Cliff Mass, is
organizing a workshop (planned for Seattle, 5-6 June 2005) to discuss
the organization of a possible Pacific field campaign during IPY to
address many of the scientific questions of THORPEX-IPY.

***CONNECTION AT NOAA LEVEL:***

The link between IPY and THORPEX is as strong at the NOAA level as
internationally. One of the ten NOAA IPY pre-proposal submissions is
THORPEX related:

+-----------------------------------------------------------------------+
| Short-Term Arctic Predictability (STAP):                              |
|                                                                       |
| A study of the variability and predictability of Arctic atmospheric,  |
| ice, ocean, and land surface events, and their interaction with       |
| global processes on the 3-90 days time scale                          |
+-----------------------------------------------------------------------+

This proposal, that was prepared by a team of ten scientists led by
Zoltan Toth (NOAA THORPEX Program Manager and Chair of the NOAA THORPEX
Science and Implementation Committee), is one of the 27 THORPEX-IPY
projects in the IPY program. The proposed work will be carried out in
the context of the broader national THORPEX-IPY activities. As of early
2005, funding for the different components of the STAP (NOAA
THORPEX-IPY) plan has not been secured. The PIs are looking for funding
sources for their THORPEX-IPY research and development work.

***PROPOSED PACIFIC FIELD CAMPAIGN:*** Members of the US THORPEX-IPY
community currently discuss the organization of a major field campaign,
coinciding with the IPY (March 2007 -- February 2009). Such a field
campaign will offer excellent opportunities to address the two
scientific hypotheses above, in a coordinated effort with other IPY
activities, and the rest of the global THORPEX community. In addition to
THORPEX-IPY, the Pacific Campaign may address other scientific issues as
well.

***THORPEX-IPY OUTCOMES:*** THORPEX-IPY will lead to improved weather,
sea ice, ocean wave, and land surface and short term climate forecasts
over the polar regions during and after the IPY, as well as improvements
to high impact weather forecasts over the mid-latitude and tropical
regions of the globe.