Integrated Global Radiosonde Archive (IGRA) at NOAA's National Climatic Data Center consists of radiosonde and pilot balloon observations at over 1500 globally distributed stations (Figure 1). Observations are available for standard, surface, tropopause and significant levels. Variables include:
- Geopotential Height
- Dewpoint Depression
- Wind Direction
- Wind Speed
The period of record varies from station to station, with many extending from 1970 to present (Figure 2). Station records are updated daily and are available online at no charge.
For additional information and access to the IGRA data, see http://www.ncdc.noaa.gov/oa/climate/igra/ .
GCOS Reference Upper-Air Network (GRUAN)
The GCOS Reference Upper Air Network is an international reference observing network, designed to meet climate requirements and to fill a major void in the current global observing system. Upper air observations within the GRUAN network will provide long-term high-quality climate records, will be used to constrain and validate data from space based remote sensors, and will provide accurate data for the study of atmospheric processes.
Since 2005 target requirements of accuracy, stability and vertical resolution have been stated and the GRUAN community called upon the hydro-meteorological equipment industry to develop a new “reference type radiosonde”.
Implementation of the network has started, involving the identification of eligible measurement sites, development of a data policy and dissemination scheme and the quest for a common mode of operations. Currently, the network comprises 15 initial sites. In 2009, the ‘GRUAN Implementation Plan 2009-2013’ has been published.
The first GRUAN-quality data will be made available in March 2011, and the network is planned to be fully operational by 2013.
GRUAN has been identified by the climate community as being required to generate long-term high quality climate records, to constrain and calibrate data from more spatially-comprehensive global observing systems (inc. satellites and current radiosonde networks) ), and to fully characterize the properties of the atmospheric column.
Comprehensive Historical Upper-Air Network (CHUAN) at ETH-Zurich provides monthly mean historical upper-air data prior to the International Geophysical Year 1957. The data set is based on 16.4 million profiles from almost 4000 station records.