Positive water vapour feedback in climate models confirmed by satellite data

Rind, David; Chiou, E. W.; Chu, William; Larsen, J. C.; Oltmans, S. J.; Lerner, J.; McCormkk, M. P.; Mcmaster, L. R.

doi:10.1038/349500a0

Cited by 166 publications

(59 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This might reduce or even reverse the water vapour feedback. On the other hand, Rind et al (1991) provide arguments for moistening of the upper troposphere as a result of global warming.…”

Section: Introductionmentioning

confidence: 99%

A distribution law for relative humidity in the upper troposphere and lower stratosphere derived from three years of MOZAIC measurements

Gierens

Schumann²,

Helten³

et al. 1999

Ann. Geophys.

190

109

View full text Add to dashboard Cite

Abstract. Data from three years of MOZAIC measurements made it possible to determine a distribution law for the relative humidity in the upper troposphere and lower stratosphere. Data amounting to 13.5% of the total were obtained in regions with ice supersaturation. Troposphere and stratosphere are distinguished by an ozone concentration of 130 ppbv as threshold. The probability of measuring a certain amount of ice supersaturation in the troposphere decreases exponentially with the degree of ice supersaturation. The probability of measuring a certain relative humidity in the stratosphere (both with respect to water and ice) decreases exponentially with the relative humidity. A stochastic model that naturally leads to the exponential distribution is provided. Mean supersaturation in the troposphere is about 15%, whereas ice nucleation requires 30% supersaturation on the average. This explains the frequency of regions in which aircraft induce persistent contrails but which are otherwise free of clouds. Ice supersaturated regions are 3±4 K colder and contain more than 50% more vapour than other regions in the upper troposphere. The stratospheric air masses sampled are dry, as expected, having mean relative humidity over water of 12% and over ice of 23%, respectively. However, 2% of the stratospheric data indicate ice supersaturation. As the MOZAIC measurements have been obtained on commercial¯ights mainly between Europe and North America, the data do not provide a complete global picture, but the exponential character of the distribution laws found is probably valid globally. Since water vapour is the most important greenhouse gas and since it might enhance the anthropogenic greenhouse e ects via positive feedback mechanisms, it is important to represent its distribution correctly in climate models. The discovery of the distribution law of the relative humidity makes possible simple tests to show whether the hydrological cycle in climate models is represented in an adequate way or not.

show abstract

“…This might reduce or even reverse the water vapour feedback. On the other hand, Rind et al (1991) provide arguments for moistening of the upper troposphere as a result of global warming.…”

Section: Introductionmentioning

confidence: 99%

A distribution law for relative humidity in the upper troposphere and lower stratosphere derived from three years of MOZAIC measurements

Gierens

Schumann²,

Helten³

et al. 1999

Ann. Geophys.

190

109

View full text Add to dashboard Cite

show abstract

“…Seasonal humidity changes [Inamdar and Ramanathan, 1998] derived from the NASA Water Vapor Project data [Randel et al, 1996] reveal a nearly unchanged relative humidity level in the lower troposphere for the tropics whereas a significant moistening occurs in the middle to upper troposphere dominated by the deep convective regions of tropics. Satellite-based observations reveal middle to upper tropospheric moistening [Rind et al, 1991] for deep convective regions for both temporal (summer-winter) and spatial (west Pacific versus east Pacific) scales. Bates and Jackson [2001], using satellite radiance observations for a 20-year period, show evidence of upper tropospheric moistening in the monsoon regions and drying in the subtropical high regions.…”

Section: Introductionmentioning

confidence: 99%

Satellite observations of the water vapor greenhouse effect and column longwave cooling rates: Relative roles of the continuum and vibration‐rotation to pure rotation bands

2004

View full text Add to dashboard Cite

[1] The Clouds and the Earth's Radiant Energy System (CERES) instrument on board the Tropical Rainfall Measuring Mission (TRMM) satellite provides, for the first time, a largescale (40 S to 40 N) data set for the atmospheric greenhouse effect and the columnaveraged longwave (LW) radiative cooling rates in the broadband (5-100 microns) and the window (8-12 microns) regions. We demonstrate here that the separation into the window and the nonwindow (5-8 microns and 12-100 microns) fluxes provides the first global-scale data set to exhibit the sensitivity of the atmospheric greenhouse effect to vertical water vapor distribution. The nonwindow greenhouse effect varies linearly with the logarithm of column water vapor amount weighted with the atmospheric pressure, while the window component varies quadratically with the water vapor partial pressure. The column cooling rates range from about À170 to À210 W m À2 for the nonwindow region. The window cooling rates are only about 10% to 20% of the above range and approach rapidly to near-zero values for surface temperatures less than 288 K. The nonwindow component of the greenhouse effect and cooling rates are shown to be more sensitive to upper troposphere water vapor, while the window greenhouse effect and cooling rates are shown to be more sensitive to the lower troposphere water vapor amount. In addition, the data reveal that in tropical regions, with warm sea surface temperatures (greater than 297 K) and elevated upper tropospheric water vapor amounts, the continuum emission in the window region leads to enhanced cooling of the column, while the rotational bands in the nonwindow region lead to a net decrease in the longwave cooling of the atmospheric column.

show abstract

“…[19] In this regard, confirmation by observations is unclear, particularly since variations due either to the seasonal cycle [e.g., Rind et al, 1991], or ENSO dominated inter annual variability [e.g., Sun and Oort, 1995] are not necessarily good surrogates for anthropogenic climate change. Nevertheless, the present study indicates that the fixed RH implications are critically important in determining overall climate sensitivity.…”

Section: Discussionmentioning

confidence: 99%

On the structure of water vapour feedbacks in climate models

Colman

2004

Geophysical Research Letters

View full text Add to dashboard Cite

[1] This paper quantifies the structure of water vapour feedback in a model by evaluating its meridional and vertical distribution and decomposing it into conceptually simplified components. First is a division into changes from fixed and varying relative humidity (RH). The first term is further divided into responses associated with the global mean surface temperature change, changes in horizontal gradients, and changes to the lapse rate. The uniform global temperature change component explains the majority of water vapour feedback. The horizontal gradient and varying RH terms are small. The component of water vapour feedback associated with lapse rate changes makes a significant contribution to the global water vapour feedback. However, there is a roughly equal and opposite temperature feedback from the lapse rate changes themselves. These results suggest both a very simple conceptual model for the bulk of the global water vapour feedback, as well as a relative insensitivity of combined temperature and water vapour feedbacks to the details of lapse rate changes. The effect of clouds on all feedback contributions is also quantified.

show abstract

Positive water vapour feedback in climate models confirmed by satellite data

Cited by 166 publications

References 7 publications

A distribution law for relative humidity in the upper troposphere and lower stratosphere derived from three years of MOZAIC measurements

A distribution law for relative humidity in the upper troposphere and lower stratosphere derived from three years of MOZAIC measurements

Satellite observations of the water vapor greenhouse effect and column longwave cooling rates: Relative roles of the continuum and vibration‐rotation to pure rotation bands

On the structure of water vapour feedbacks in climate models

Contact Info

Product

Resources

About