Transport Changes Inferred from HALOE Water and Methane Measurements.

Rosenlof, Karen H.

doi:10.2151/jmsj.80.831

Cited by 52 publications

(62 citation statements)

References 31 publications

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“…A positive trend for CH 4 in this region implies a decreasing (or ). That initial acceleration of the BDC was likely followed by an extended period of negative CH 4 trends, as reported by Rosenlof (2002) and Nedoluha et al (1998). Randel et al (1999) also reported on a rather episodic rebound for the CH 4 of the lower mesosphere in 1997-1998.…”

Section: Trends In Ch 4 From the Troposphere And In The Stratospheresupporting

confidence: 54%

“…1) for the time span of 1991-1997, by Randel et al (1999, their Fig. 4) for 1992-1999, and even by Rosenlof (2002Rosenlof ( ) for 1992Rosenlof ( -2001. An analysis of the HALOE data is carried out for the latitude zone of 10 • S to 10 • N, but for the entire time period of 1991-2005; the MLR fit to that particular time series is shown in Fig.…”

Section: Trends In Ch 4 From the Troposphere And In The Stratospherementioning

confidence: 93%

“…The exact latitude location of the maximum gradient varies seasonally, according to the strength of the meridional mixing of the air masses that occurred in the weeks before. Latitude versus pressurealtitude cross sections of the CH 4 from the HALOE Website (http://haloe.gats-inc.com/home/) for October of successive years reveal that the isolines of the tropical CH 4 distribution did not extend into the upper stratosphere during , 1993, 1995, and 2004, while they were elevated in 1992, 2002, and 2003. CH 4 variations for 1996 were intermediate to those of the other years.…”

Section: Analysis Approachmentioning

confidence: 95%

“…The present analysis study makes use of time series of CH 4 mixing ratio data as a function of pressure altitude for 1992-2005 from the Halogen Occultation Experiment (HALOE) aboard the Upper Atmosphere Research Satellite (UARS). As noted by Rosenlof (2002) and by Neu et al (2003), atmospheric sampling via the method of solar occultation is adequate typically for obtaining the large-scale seasonal variations of CH 4 . The HALOE instrument obtained sunrise (SR) and sunset (SS) profiles of CH 4 in the stratosphere and lower mesosphere, and a number of researchers have made use of its CH 4 data for studies of middle atmosphere transport.…”

Section: Objectivesmentioning

confidence: 99%

“…Still, for the lower latitudes HALOE typically made its measurements across a given latitude bin over just a few days, due to the alternating nature of the time sequence of its SR and SS occultations from the UARS satellite. Rosenlof (2002) combined the SR and SS measurements within 5 • bins and calculated their monthly averages. However, in the present study the SR and SS profiles are averaged separately.…”

Section: Analysis Approachmentioning

confidence: 99%

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Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

Remsberg

2015

Atmos. Chem. Phys.

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Abstract. This study makes use of time series of methane (CH 4 ) data from the Halogen Occultation Experiment (HALOE) to detect whether there were any statistically significant changes of the Brewer-Dobson circulation (BDC) within the stratosphere during 1992-2005. The HALOE CH 4 profiles are in terms of mixing ratio versus pressure altitude and are binned into latitude zones within the Southern Hemisphere and the Northern Hemisphere. Their separate time series are then analyzed using multiple linear regression (MLR) techniques. The CH 4 trend terms for the Northern Hemisphere are significant and positive at 10 • N from 50 to 7 hPa and larger than the tropospheric CH 4 trends of about 3 % decade −1 from 20 to 7 hPa. At 60 • N the trends are clearly negative from 20 to 7 hPa. Their combined trends indicate an acceleration of the BDC in the middle stratosphere of the Northern Hemisphere during those years, most likely due to changes from the effects of wave activity. No similar significant BDC acceleration is found for the Southern Hemisphere. Trends from HALOE H 2 O are analyzed for consistency. Their mutual trends with CH 4 are anti-correlated qualitatively in the middle and upper stratosphere, where CH 4 is chemically oxidized to H 2 O. Conversely, their mutual trends in the lower stratosphere are dominated by their trends upon entry to the tropical stratosphere. Time series residuals for CH 4 in the lower mesosphere also exhibit structures that are anti-correlated in some instances with those of the tracer-like species HCl. Their occasional aperiodic structures indicate the effects of transport following episodic, wintertime wave activity. It is concluded that observed multi-year, zonally averaged distributions of CH 4 can be used to diagnose major instances of wave-induced transport in the middle atmosphere and to detect changes in the stratospheric BDC.

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Section: Trends In Ch 4 From the Troposphere And In The Stratospheresupporting

confidence: 54%

Section: Trends In Ch 4 From the Troposphere And In The Stratospherementioning

confidence: 93%

Section: Analysis Approachmentioning

confidence: 95%

Section: Objectivesmentioning

confidence: 99%

Section: Analysis Approachmentioning

confidence: 99%

See 3 more Smart Citations

Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

Remsberg

2015

Atmos. Chem. Phys.

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The Structure of O₃/H₂O Mixing Relationships in the Tropopause Transition Layer at Middle and High Latitudes of the Northern Hemisphere

Wang

Zuo

Wang

et al. 2010

Chinese J of Geophysics

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Using HALOE O3 and H2O vertical profiles in 40°N~50°N of the Northern Hemisphere, considering chemical lifetime and transport temporal constant of O3 and H2O, the structure and seasonal characteristic of O3/H2O mixing relationships between 300 K to 390 K near the tropopause and the lowest stratosphere have been constructed in the isentropic coordinates. The results are as follows: (1) The slope of O3 mixing ratios profile has a spatial sudden change between 320~380 K isentropic surfaces of the tropopause translation layer, while the slope of H2O mixing ratios profile exhibits a spatial gradual change. The source region of O3 is stratosphere but H2O is troposphere near tropopause. So on the two sides of 320~380 K isentropic surfaces, mixing ratios of O3 and H2O show distinctly different vertical gradient. (2) In the vicinity of the tropopause where O3/H2O relationships reach best least square fitting, the troposphere and stratospheric branch of the non‐regular “L” relationship show seasonal and intra‐seasonal changes with a negative slope in tropospheric branch, but positive and negative slopes alter with seasons in stratospheric branch. At the same time, based on the “L” corner, the characteristic of chemopause with seasons can be confirmed. (3) The O3/H2O mixing relationship indicates that the transition layer is formed by stratospheric mixing with tropospheric air masses from different regions, and the mixing line of the transition layer is not constant. The transition layer mixing is equivalent in January, April 2003 and in January 2005, about 30 K isentropic thickness, that is between 320~350 K isentropic surfaces. Mixing height increases in November 2005, and the H2O coming into the stratosphere is less than in January 2003 and 2005, with about 30 K isentropic thickness, between 330~360 K isentropic surfaces. The change of mixing isentropic thickness is small in different seasons, but mixing height changes with seasons. The stratospheric branch of O3/H2O mixing relationship obviously changes with seasons, for which the significant reason is the lowest stratospheric air dehydration in January.

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Poleward expansion of the tropical belt derived from upper tropospheric water vapour

et al. 2014

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Based on intersatellite-calibrated high-resolution infrared radiation sounder (HIRS) upper tropospheric water vapour (UTWV) brightness temperatures, the width of the tropical belt is defined as the distance between the latitudes at which maximum HIRS UTWV brightness temperatures are recorded in both hemispheres. Poleward expansion of the tropical belt is evident during 1979-2013 on an annual basis, with an average global magnitude of 1.57 ∘ latitude per decade. Most rapid widening is evident in the west Pacific, in agreement with the strengthening of the Walker Circulation over time. This research suggests that the HIRS UTWV brightness temperatures are a good proxy to investigate the expansion of the tropical circulation in low latitudes.

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Transport Changes Inferred from HALOE Water and Methane Measurements.

Cited by 52 publications

References 31 publications

Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

The Structure of O₃/H₂O Mixing Relationships in the Tropopause Transition Layer at Middle and High Latitudes of the Northern Hemisphere

Poleward expansion of the tropical belt derived from upper tropospheric water vapour

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Transport Changes Inferred from HALOE Water and Methane Measurements.

Cited by 52 publications

References 31 publications

Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

The Structure of O3/H2O Mixing Relationships in the Tropopause Transition Layer at Middle and High Latitudes of the Northern Hemisphere

Poleward expansion of the tropical belt derived from upper tropospheric water vapour

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The Structure of O₃/H₂O Mixing Relationships in the Tropopause Transition Layer at Middle and High Latitudes of the Northern Hemisphere