AGW Observer

Observations of anthropogenic global warming

Papers on stratospheric water vapor

Posted by Ari Jokimäki on May 15, 2010

This is a list of papers on stratospheric water vapor. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

Contributions of Stratospheric Water Vapor to Decadal Changes in the Rate of Global Warming – Solomon et al. (2010) “Stratospheric water vapor concentrations decreased by about 10% after the year 2000. Here we show that this acted to slow the rate of increase in global surface temperature over 2000–2009 by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases. More limited data suggest that stratospheric water vapor probably increased between 1980 and 2000, which would have enhanced the decadal rate of surface warming during the 1990s by about 30% as compared to estimates neglecting this change. These findings show that stratospheric water vapor is an important driver of decadal global surface climate change.” [Full text]

Simulation of secular trends in the middle atmosphere, 1950–2003 – Garcia et al. (2007) “We have used the Whole Atmosphere Community Climate Model to produce a small (three-member) ensemble of simulations of the period 1950–2003. … Calculated trends in water vapor, on the other hand, are not at all consistent with observations from either the HALOE satellite instrument or the Boulder, Colorado, hygrosonde data set. We show that such lack of agreement is actually to be expected because water vapor has various sources of low-frequency variability (heating due to volcanic eruptions, the quasi-biennial oscillation and El Niño–Southern Oscillation) that can confound the determination of secular trends.” [Full text]

Decreases in stratospheric water vapor after 2001: Links to changes in the tropical tropopause and the Brewer-Dobson circulation – Randel et al. (2006) “Time series of stratospheric water vapor measurements by satellites and balloons show persistent low values beginning in 2001. … The results paint a consistent picture of enhanced tropical upwelling after 2001, resulting in colder temperatures, lower water vapor and lower ozone near the tropical tropopause.” [Full text]

Control of interannual and longer-term variability of stratospheric water vapor – Fueglistaler & Haynes (2005) “We use trajectory calculations based on 40-year European Reanalysis (ERA-40) data to predict the water mixing ratio of air entering the stratosphere in the tropics ([H2O]e) and thereby to examine interannual and longer-term changes. [H2O]e is determined from the saturation mixing ratio of the coldest point during ascent from the troposphere to the stratosphere (the Lagrangian cold point). These model predictions for the time variation of [H2O]e agree very well with a broad range of measurements (Stratospheric Aerosol and Gas Experiment (SAGE) II, Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS), and Atmospheric Trace Molecule Spectroscopy (ATMOS)). … The combination of measurement uncertainties and relatively strong interannual variability with periods of several months to years, on the one hand, limits our ability to detect, attribute, and verify long-term trends and, on the other hand, raises the question as to whether the previously published estimates of long-term trends are too large.”

Interannual Changes of Stratospheric Water Vapor and Correlations with Tropical Tropopause Temperatures – Randel et al. (2004) “Interannual variations of stratospheric water vapor over 1992–2003 are studied using Halogen Occultation Experiment (HALOE) satellite measurements. Interannual anomalies in water vapor with an approximate 2-yr periodicity are evident near the tropical tropopause, and these propagate vertically and latitudinally with the mean stratospheric transport circulation (in a manner analogous to the seasonal “tape recorder”). Unusually low water vapor anomalies are observed in the lower stratosphere for 2001–03. These interannual anomalies are also observed in Arctic lower-stratospheric water vapor measurements by the Polar Ozone and Aerosol Measurement (POAM) satellite instrument during 1998–2003. Comparisons of the HALOE data with balloon measurements of lower-stratospheric water vapor at Boulder, Colorado (40°N), show partial agreement for seasonal and interannual changes during 1992–2002, but decadal increases observed in the balloon measurements for this period are not observed in HALOE data. Interannual changes in HALOE water vapor are well correlated with anomalies in tropical tropopause temperatures. The approximate 2-yr periodicity is attributable to tropopause temperature changes associated with the quasi-biennial oscillation and El Niño–Southern Oscillation.” [Full text]

Assessing the climate impact of trends in stratospheric water vapor – Forster & Shine (2002) “It is now apparent that observed increases in stratospheric water vapor may have contributed significantly to both stratospheric cooling and tropospheric warming over the last few decades. However, a recent study has suggested that our initial estimate of the climate impact may have overestimated both the radiative forcing and stratospheric cooling from these changes. We show that differences between the various estimates are not due to inherent problems with broadband and narrow-band radiation schemes but rather due to the different experimental setups, particularly the altitude of the water vapor change relative to the tropopause used in the radiative calculations. Furthermore, we show that if recent estimates for the observed water vapor trends are valid globally they could have contributed a radiative forcing of up to 0.29 Wm−2 and a lower-stratospheric cooling of more than 0.8 K over the past 20 years, with these values more than doubling if, as has been suggested, the trend has persisted for the last 40 years. This 40 year radiative forcing is roughly 75% of that due to carbon dioxide alone but, despite its high value, we find that the addition of this forcing into a simple model of climate change still gives global mean surface temperature trends which are consistent with observations.” [Full text]

Stratospheric water vapor increases over the past half‐century – Rosenlof et al. (2001) “Ten data sets covering the period 1954–2000 are analyzed to show a 1%/yr increase in stratospheric water vapor. The trend has persisted for at least 45 years, hence is unlikely the result of a single event, but rather indicative of long‐term climate change. A long‐term change in the transport of water vapor into the stratosphere is the most probable cause.”

Radiative forcing due to trends in stratospheric water vapour – Smith et al. (2001) “Trends derived from the latest version of Halogen Occultation Experiment (HALOE) data are used in a two‐dimensional atmospheric model to estimate their radiative effects over the last decade. The results show a stratospheric cooling in regions of H2O increase, of magnitude similar to that due to stratospheric ozone loss indicating a significant additional cause of observed stratospheric temperature decreases. Radiative forcings are derived and it is found that global average radiative forcing due to stratospheric water vapour changes probably lies in the range 0.12 to 0.20 Wm−2 decade−1. This could have more than compensated for the negative radiative forcing due to decadal ozone loss.” [Full text]

Climate and ozone response to increased stratospheric water vapor – Shindell (2001) “Stratospheric water vapor abundance affects ozone, surface climate, and stratospheric temperatures. From 30–50 km altitude, temperatures show global decreases of 3–6 K over recent decades. These may be a proxy for water vapor increases, as the GISS climate model reproduces these trends only when stratospheric water vapor is allowed to increase. Observations suggest that stratospheric water vapor is indeed increasing, though measurements are extremely limited in either spatial coverage or duration. Model results suggest that the observed changes may be part of a global, long‐term trend. Furthermore, the required water vapor change cannot be accounted for by increased stratospheric production, suggesting that climate change may be altering tropospheric input. The calculated water vapor increase contributes an additional ≈ 24% (≈ 0.2 W/m²) to the global warming from well‐mixed greenhouse gases over the past two decades. Observed ozone depletion is also better reproduced when destruction due to increased water vapor is included. If the trend continues, it could increase future global warming and impede stratospheric ozone recovery.”

The increase in stratospheric water vapor from balloonborne, frostpoint hygrometer measurements at Washington, D.C., and Boulder, Colorado – Oltmans et al. (2000) “Stratospheric water vapor concentrations measured at two midlatitude locations in the northern hemisphere show water vapor amounts have increased at a rate of 1–1.5% yr−1 (0.05–0.07 ppmv yr−1) for the past 35 years. At Washington, D.C., measurements were made from 1964–1976, and at Boulder, Colorado, observations began in 1980 and continue to the present. While these two data sets do not comprise a single time series, they individually show increases over their respective measurement periods. At Boulder the trends do not show strong seasonal differences; significant increases are found throughout the year in the altitude range 16–28 km. In winter these trends are significant down to about 13 km.” [Full text]

SPARC Assessment of Upper Tropospheric and Stratospheric Water Vapour – Kley et al. (2000) A report on the subject. [Full text available in the abstract page]

Stratospheric water vapour changes as a possible contributor to observed stratospheric cooling – Forster & Shine (1999) “The observed cooling of the lower stratosphere over the last two decades has been attributed, in previous studies, largely to a combination of stratospheric ozone loss and carbon dioxide increase, and as such it is meant to provide one of the best pieces of evidence for an anthropogenic cause to climate change. This study shows how increases in stratospheric water vapour, inferred from available observations, may be capable of causing as much of the observed cooling as ozone loss does; as the reasons for the stratospheric water vapour increase are neither fully understood nor well characterized, it shows that it remains uncertain whether the cooling of the lower stratosphere can yet be fully attributable to human influences. In addition, the changes in stratospheric water vapour may have contributed, since 1980, a radiative forcing which enhances that due to carbon dioxide alone by 40%.”

Mechanisms controlling water vapor in the lower stratosphere: “A tale of two stratospheres” – Dessler et al. (1995) “We present an analysis of the mechanisms controlling stratospheric water vapor based on in situ profiles made at 37.4°N and at altitudes up to 20 km. The stratosphere can be conveniently divided into two air masses: the overworld (potential temperature θ > 380 K) and the lowermost stratosphere (θ < 380). Our data support the canonical theory that air primarily enters the overworld by passing through the tropical tropopause. The low water vapor mixing ratios in the overworld, a few parts per million by volume (ppmv), are determined by the low temperatures encountered at the tropical tropopause, as well as oxidation of methane and molecular hydrogen. Air enters the lowermost stratosphere both by diabatically descending from the overworld across the 380-K potential temperature surface and by passing through the extratropical tropopause. Air parcels crossing the extratropical tropopause experience higher temperatures than air crossing the tropical tropopause, allowing higher water vapor in the lowermost stratosphere (tens of ppmv) than in the overworld. Our data are consistent with the pathway for air crossing the extratropical tropopause being isentropic advection from lower latitudes, although we cannot exclude contributions from other paths.” [Full text]

Overview of the Stratospheric Aerosol and Gas Experiment II Water Vapor Observations: Method, Validation, and Data Characteristics – Rind et al. (1993) “Water vapor observations obtained from the Stratospheric Aerosol and Gas Experiment II (SAGE II) solar occultation instrument for the troposphere and stratosphere are presented and compared with correlative in situ measurement techniques and other satellite data. … …minimum water vapor values of 2.5–3 ppmv in the tropical lower stratosphere, with lower values during northern hemisphere winter and spring; slowly increasing water vapor values with altitude in the stratosphere, reaching 5–6 ppmv or greater near the stratopause; extratropical values with minimum profile amounts occurring above the conventionally defined tropopause; and higher extratropical than tropical water vapor values throughout the stratosphere except in locations of possible polar stratospheric clouds.”

Stratospheric Water Vapor – Ellsaesser (1983) “We present a tutorial review of our understanding of stratospheric H2O and the processes controlling it. We attempt to synthesize a consistent global picture that requires rejection of a minimum of the conflicting observational data. As such, this synthesis is determined somewhat by the personal opinions and beliefs of the author. We note the paradoxes posed by currently available observational data and suggest ways they might be resolved.”

The distribution of water vapor in the stratosphere – Harries (1976) “This paper seeks to collect together and to assess the many measurements of stratospheric humidity which have been reported over the last 25 years, with a view to determining the average distribution of water vapor in the stratosphere and its variations in time and space. Variations with height, latitude, time, and season are considered. In addition, some consideration is given to the proper use of experimental values of humidity in discussions of the water budget and circulation of the stratosphere; it is emphasized that the considerable uncertainties which often exist in measured data often can preclude the drawing of quantitative conclusions.”

Water Vapor Distribution in the Stratosphere and High Troposphere – Mastenbrook (1968) “Fifty-one soundings with balloon-borne frost-point hygrometers provided measurements to a height of 94,000 ft of the vertical distribution of water vapor over Trinidad, West Indies, Washington, D.C., and Thule, Greenland, during 1964 and 1965, the International Years of the Quiet Sun. … The observed mixing ratios of the lower stratosphere to a height of 73,000 ft are for nearly all cases within the range of 1.2 × 10−6 – 3.3 × 10−6.” [Full text]

One Response to “Papers on stratospheric water vapor”

  1. Ari Jokimäki said

    I added Fueglistaler & Haynes (2005), Kley et al. (2000) and Ellsaesser (1983) from atmospheric water vapor list.

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