Upper-air Temperature

	Temperature is one of the fundamental state variables for understanding and predicting the behaviour of the atmosphere. It is basic to the energy budget of the climate system as a whole through the temperature dependence of the long-wave radiation of energy from the atmosphere to space. Upper-air observations are of key importance for detecting and attributing climate change in the troposphere and stratosphere because the warming of the troposphere and the cooling of the stratosphere are unique fingerprints of anthropogenic GHG. They are needed for the development and evaluation of climate models, and for the initialization of medium term and seasonal forecasts.
	Domain:	Atmosphere
	Subdomain:	Surface
	Scientific Area:	Energy and Temperature
	ECV Steward:
	Products:	Atmospheric Temperature in the Boundary Layer, in the Upper Troposphere and Lower Stratosphere, in the Free Troposphere, in the Middle and Upper Stratosphere, in the Mesophere

Global Upper-air Temperature

Figure: Zonal mean atmospheric temperature change from 1890 to 1999 (°C per century) as simulated by the PCM model as sum of solar forcing, volcanoes, well-mixed greenhouse gases, tropospheric and stratospheric ozone changes, direct sulphate and aerosol forcing. Plot is from 1,000 hPa to 10 hPa (shown on left scale) and from 0 km to 30 km (shown on right).

Source : Adapted from Figure 9.1,IPCC, 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 996 pp.

ECV Products and Requirements

These products and requirements reflect the Implementation Plan 2022 (GCOS-244).

The requirements are found in the complete 2022 ECVs Requirements document as well: ECV Upper-air Temperature.

Products	Atmospheric Temperature in the
Products			Boundary Layer	Upper Troposphere and Lower Stratosphere		Free Troposphere	Middle and Upper Stratosphere	Mesosphere
	(*)	Unit	Values	Values	Unit	Values	Values	Values
Horizontal Resolution	G	km	15	15	km	15	50	50
	B		100	100		100	100	100
	T		500	500		1000	1500	1500
Vertical Resolution	G	m	1	25	km	0.01	0.5	0.5
	B		10	100		0.1	1	1
	T		100	250		1	3	3
Temporal Resolution	G	h	<1	1	h	1	1	1
	B		6	12		12	12	12
	T		12	24		24	24	24
Timeliness	G	h	1	1	h	1	1	1
	B		3	3		3	3	3
	T		24	6		6	6	6
Required Measurement Uncertainty (2-sigma)	G	K	0.1	0.1	K	0.1	0.1	0.1
	B		0.5	0.5		0.5	0.5	0.5
	T		1	1		1	1	1
Stability	G	K/decade	0.01	0.01	K/decade	0.01	0.05	0.05
	B		0.05	0.02		0.02	0.1	0.1
	T		0.1	0.05		0.05	0.2	0.2

(*) Goal (G): an ideal requirement above which further improvements are not necessary. Breakthrough (B): an intermediate level between threshold and goal which, if achieved, would result in a significant improvement for the targeted application. The breakthrough value may also indicate the level at which specified uses within climate monitoring become possible. It may be appropriate to have different breakthrough values for different uses. Threshold (T): the minimum requirement to be met to ensure that data are useful

Data Sources

This list provides sources for openly accessible data sets with worldwide coverage for which metadata is available. It is curated by the respective GCOS ECV Steward(s). The list does not claim to be complete. Anyone with a suitable dataset who wishes it to be added to this list should contact the GCOS Secretariat.