GLOBAL CLIMATE OBSERVING SYSTEM- REQUIREMENTS AND REALITIES OF PROVIDING OVERLAPPING RADIOSONDE FLIGHT SERIES DATA FOR LONG TERM CLIMATE CONTINUITY Carl.

GLOBAL CLIMATE OBSERVING SYSTEM-REQUIREMENTS AND REALITIES OF

PROVIDING OVERLAPPING RADIOSONDE FLIGHT SERIES DATA FOR LONG TERM

CLIMATE CONTINUITY

GLOBAL CLIMATE OBSERVING SYSTEM-REQUIREMENTS AND REALITIES OF

PROVIDING OVERLAPPING RADIOSONDE FLIGHT SERIES DATA FOR LONG TERM

CLIMATE CONTINUITY

Carl A. Bower, Jr.NOAA National Weather Service

TECO 2006World Meteorological Organization

Geneva, Switzerland

Carl A. Bower, Jr.NOAA National Weather Service

TECO 2006World Meteorological Organization

Geneva, Switzerland

GCOS Upper-air Network Composition and IssuesGCOS 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 RegionRadiosonde Vendors GUAN Sites by WMO Region

GCOS Continuity RecommendationsGCOS 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

• 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 ContinuityNWS 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

• 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 SitesThe 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

• 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 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

• 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 typesMajor 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

• 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 characteristicsNWS 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

• 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 FlightsRadiosonde 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

• 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

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

• 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

World Meteorological Organization Regional Instrumentation Centers

Region Location

1 Africa Oran, Algeria Cairo, EgyptNairobi, KenyaGaborone, Botswana

2 Asia Beijing, ChinaTsukuba, Japan

3 South America Meteorological Laboratoryand Workshop of theNational Meteorological Service of Argentina

4 North and Central

America

Mt Washington, New HampshireThe Caribbean MeteorologicalInstitute of BarbadosRMTC, San Jose, Costa Rica

5 Southwest Pacific

Melbourne, Australia (Regional Radiation Center)

6 Europe Service des equipments et des techniquesinstrumentals de la meteorology, Trappes, France

RIC Site Expansion RequiredRIC 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

• 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 RegionRadiosonde Vendors GUAN Sites by WMO Region

ConclusionsConclusions

• 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

• 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