Seasonal to decadal variations of water vapor in the tropical lower stratosphere observed with balloon‐borne cryogenic frost point hygrometers

Fujiwara, Masatomo; Vömel, H.; Hasebe, Fumio; Shiotani, Masato; Ogino, Shin-Ya; Iwasaki, S.; Nishi, Noriyuki; Shibata, Takashi; Shimizu, Kensaku; Nishimoto, Eriko; Canossa, Jéssica María Valverde; Selkirk, Henry B.; Oltmans, S. J.

doi:10.1029/2010jd014179

Cited by 74 publications

(84 citation statements)

References 49 publications

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“…Middle atmosphere water has been increasing in part due to the increase in CH 4 although there are also trends in the water entering from the troposphere to the stratosphere over the past several decades (Fujiwara et al 2010). Trends in HOx have an important impact on mesospheric ozone, which is important for the radiative balance in the MLT (both as an absorber of solar ultraviolet radiation and as a component in chemical heating).…”

Section: Long-term Trendsmentioning

confidence: 99%

Global Dynamics of the MLT

2012

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The transition between the middle atmosphere and the thermosphere is known as the MLT region (for mesosphere and lower thermosphere). This area has some characteristics that set it apart from other regions of the atmosphere. Most notably, it is the altitude region with the lowest overall temperature and has the unique characteristic that the temperature is much lower in summer than in winter. The summer-to-winter-temperature gradient is the result of adiabatic cooling and warming associated with a vigorous circulation driven primarily by gravity waves. Tides and planetary waves also contribute to the circulation and to the large dynamical variability in the MLT. The past decade has seen much progress in describing and understanding the dynamics of the MLT and the interactions of dynamics with chemistry and radiation. This review describes recent observations and numerical modeling as they relate to understanding the dynamical processes that control the MLT and its variability. Results from the Whole Atmosphere Community Climate Model (WACCM), which is a comprehensive high-top general circulation model with interactive chemistry, are used to illustrate the dynamical processes. Selected observations from the Sounding the Atmosphere with Broadband Emission Radiometry (SABER) instrument are shown for comparison. WACCM simulations of MLT dynamics have some differences with observations. These differences and other questions and discrepancies described in recent papers point to a number of ongoing uncertainties about the MLT dynamical system.

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Section: Long-term Trendsmentioning

confidence: 99%

Global Dynamics of the MLT

2012

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“…understood, whereas the dehydration process in the tropical tropopause region is somewhat unclear despite the fact that it is considered a key factor for understanding stratospheric water vapor, including its unexplained long-term change (Oltmans and Hofmann, 1995;Kley et al, 2000;Oltmans et al, 2000;Scherer et al, 2008;Fujiwara et al, 2010;Hurst et al, 2011).…”

Section: Y Inai Et Al: Water Vapor Matchmentioning

confidence: 99%

Dehydration in the tropical tropopause layer estimated from the water vapor match

et al. 2013

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We apply the match technique, whereby the same air mass is observed more than once and such cases are termed a "match", to study the dehydration process associated with horizontal advection in the tropical tropopause layer (TTL) over the western Pacific. The matches are obtained from profile data taken by the Soundings of Ozone and Water in the Equatorial Region (SOWER) campaign network observations using isentropic trajectories calculated from European Centre for Medium-Range Weather Forecasts (ECMWF) operational analyses. For the matches identified, extensive screening procedures are performed to verify the representativeness of the air parcel and the validity of the isentropic treatment, and to check for possible water injection by deep convection, consistency between the sonde data and analysis field referring to the ozone conservation. Among the matches that passed the screening tests, we identified some cases corresponding to the first quantitative value of dehydration associated with horizontal advection in the TTL. The statistical features of dehydration for the air parcels advected in the lower TTL are derived from the matches. The threshold of nucleation is estimated to be 146 ± 1% (1σ) in relative humidity with respect to ice (RH_ice), while dehydration seems to continue until RH_ice reaches about 75 ± 23% (1σ) in the altitude region from 350 to 360 K. The efficiency of dehydration expressed by the relaxation time required for the supersaturated air parcel to approach saturation is empirically determined from the matches. A relaxation time of approximately one hour reproduces the second water vapor observation reasonably well, given the first observed water vapor amount and the history of the saturation mixing ratio during advection in the lower TTL

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“…Data include routine monitoring from Boulder, CO; Hilo, HI; Lauder, NZ; and Lindenberg, Germany. The field campaign projects include the Soundings of Ozone and Water in the Equatorial Region (SOWER) project at sites in Indonesia, Vietnam, Kiribati, and Ecuador (Hasebe et al, 2013;Fujiwara et al, 2010), the Ticosonde project at San Jose in Costa Rica (Fujiwara et al, 2010;Selkirk et al, 2010), the Sounding Water vapor, Ozone and Particle (SWOP) project at sites in China except for Yangjiang (Bian et al, 2012), the 8th World Meteorological Organization (WMO) Intercomparison of High Quality Radiosonde Systems in Yanjiang, China , and the research vessel Mirai campaign in the tropical Indian Ocean (Suzuki et al, 2013). Matched satellite profiles are found by searching for any profiles within a given time, distance, and equivalent latitude range of the FP data.…”

Section: Frost Point Hygrometer Comparisonsmentioning

confidence: 99%

The Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database: a long-term database for climate studies

Davis

Rosenlof

Haßler

et al. 2016

Earth Syst. Sci. Data

164

195

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Abstract. In this paper, we describe the construction of the Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database, which includes vertically resolved ozone and water vapor data from a subset of the limb profiling satellite instruments operating since the 1980s. The primary SWOOSH products are zonal-mean monthly-mean time series of water vapor and ozone mixing ratio on pressure levels (12 levels per decade from 316 to 1 hPa). The SWOOSH pressure level products are provided on several independent zonal-mean grids (2.5, 5, and 10 • ), and additional products include two coarse 3-D griddings (30 • long × 10 • lat, 20 • × 5 • ) as well as a zonal-mean isentropic product. SWOOSH includes both individual satellite source data as well as a merged data product. A key aspect of the merged product is that the source records are homogenized to account for inter-satellite biases and to minimize artificial jumps in the record. We describe the SWOOSH homogenization process, which involves adjusting the satellite data records to a "reference" satellite using coincident observations during time periods of instrument overlap. The reference satellite is chosen based on the best agreement with independent balloon-based sounding measurements, with the goal of producing a long-term data record that is both homogeneous (i.e., with minimal artificial jumps in time) and accurate (i.e., unbiased). This paper details the choice of reference measurements, homogenization, and gridding process involved in the construction of the combined SWOOSH product and also presents the ancillary information stored in SWOOSH that can be used in future studies of water vapor and ozone variability. Furthermore, a discussion of uncertainties in the combined SWOOSH record is presented, and examples of the SWOOSH record are provided to illustrate its use for studies of ozone and water vapor variability on interannual to decadal timescales. The version 2.5 SWOOSH data are

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Seasonal to decadal variations of water vapor in the tropical lower stratosphere observed with balloon‐borne cryogenic frost point hygrometers

Cited by 74 publications

References 49 publications

Global Dynamics of the MLT

Global Dynamics of the MLT

Dehydration in the tropical tropopause layer estimated from the water vapor match

The Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database: a long-term database for climate studies

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