Transcript GLOBAL CLIMATE OBSERVING SYSTEMREQUIREMENTS AND REALITIES OF PROVIDING OVERLAPPING RADIOSONDE FLIGHT SERIES DATA FOR LONG TERM CLIMATE CONTINUITY Carl A.

GLOBAL CLIMATE OBSERVING SYSTEMREQUIREMENTS AND REALITIES OF
PROVIDING OVERLAPPING RADIOSONDE
FLIGHT SERIES DATA FOR LONG TERM
CLIMATE CONTINUITY
Carl A. Bower, Jr.
NOAA National Weather Service
TECO 2006
World Meteorological Organization
Geneva, Switzerland
GCOS Upper-air Network Composition and Issues
•163 GUAN sites in WMO Regions
•6 Radiosonde Manufacturers
•67 Countries make up GUAN
•40% of GUAN network launches one or fewer radiosondes per day
•Recommended overlapping flight series is costly
•On-going changes in the GUAN
–Radiosonde changes
–Algorithm changes
–Provider changes
Radiosonde Vendors GUAN Sites by WMO Region
GCOS Continuity Recommendations
• Maintain historical data series for long-term climate
trends analysis
• GUAN sites to use one radiosonde type for as long as
feasible
• Overlapping flight series of the old radiosonde and the
new radiosonde if change is required
– At selected representative sites
– One-year overlap
• Comparison data used to formulate bias transfer
functions for application to new data
NWS Policy on Data Continuity
• NWS recognizes importance of long-term climate records
stability
• NWS policy is to:
– To conduct intercomparison studies as new instruments are
introduced to the network
– To determine transfer functions between old and new sensors
– To determine differences at representative locations
• Differences related to sensor change
• Differences related to spatial separation
• Implementation not started—GUAN sites not impacted
The Realities of Providing Overlapping
Flight Series Data for NWS GUAN Sites
•
17 National Weather Service
GUAN sites
•
Sites cover
– Equatorial tropics
– Mid latitudes
– Arctic
•
US climate community
designated all NWS GUAN as
continuity sites
•
NWS replacing all sites with
GPS-based systems
•
All sites continuity is not
affordable nor necessary
Selecting Representative GUAN Sites for Continuity
Flights
•
Weatherhead determined
temperature trends per decade
from 40-year period of record
•
Nine stations selected from 3
different regions in United
States
•
Means and standard deviations
by pressure level are different
between stations within a
region
•
Trends appear to be regional
but are remarkably similar
within a region
Major North American Air Mass types
• Weatherhead’s upper air
data trend similarity
analysis was impetus to
down select climate
continuity from 17 sites
• Results were consistent
with air-mass source
regions
• NWS network impacted by
6 major air mass regions
• No more than 5 to 8 sites
for test
NWS GUAN Sites with Air Mass Areas defining
overarching characteristics
• Petersen grouped NWS
GUAN sites into climate
regions.
• Seven regions identified
for GUAN locations
• Regions include tropical,
maritime polar, Artic and
continental polar stations
• One representative site
selected for each region
Radiosonde Functional Comparison Flights
•
Up to one year of radiosonde
comparison flights
– Minimum 200 flights for four
season sites
– Minimum of 100 flights for two
season sites
– Day and night flights
•
Change of radiosonde types,
sensor suites or transfer equations
•
Representative locations selected
based on climate regions
•
Determine bias transfer functions
The Realities of Providing Overlapping Flight
Series Data for International GUAN Sites
• Nash recognized the difficulty for International sites to
conduct overlapping continuity flight series
– 67 countries
– Numerous radiosonde types
– Rapid evolution of new radiosondes and replacement of old
radiosondes
– Lack of overlapping flights for new Vaisala sondes, Modem
sondes, Sippican sondes etc
• Proposed to Expert Team that RICs could possibly
perform series
• Proposed funding be procured and ground systems be
placed at RICs
World Meteorological Organization Regional
Instrumentation Centers
Region
Location
1 Africa
Oran, Algeria Cairo, Egypt
Nairobi, Kenya
Gaborone, Botswana
2 Asia
Beijing, China
Tsukuba, Japan
3 South America
Meteorological Laboratory
and Workshop of the
National Meteorological
Service of Argentina
4 North and
Central
America
Mt Washington, New Hampshire
The Caribbean Meteorological
Institute of Barbados
RMTC, San Jose, Costa Rica
5 Southwest
Pacific
Melbourne, Australia (Regional
Radiation Center)
6 Europe
Service des equipments et des techniques
instrumentals de la meteorology, Trappes, France
RIC Site Expansion Required
•
Some global areas not
represented by RICs
•
Region VI lacks RIC
•
Arctic representation required
•
Most GUAN sites are or will be
flying new radiosondes without
having overlapping studies at
representative locations
Radiosonde Vendors GUAN Sites by WMO Region
Conclusions
• 1-year overlapping flight series is hard to satisfy:
– Continuous changes in technology impact long term
continuity
– Fewer sites still large task with 6 different radiosonde
providers
• Many countries/Regions cannot afford cost of continuity
• RICs may have potential if funded by climate programs
– Issues with representative spatial measurements
– More and different sites required
– Require redundant ground stations for overlapping
flight series
• No known flight series performed:
– RS80/RS92
– Vaisala/Modem
– Individual country modernization