Troposphere‐to‐stratosphere transport in the lowermost stratosphere from measurements of H2O, CO2, N2O and O3

The origin of air in the lowermost stratosphere is investigated with measurements from the NASA ER‐2 aircraft. Air with high water vapor mixing ratios was observed in the stratosphere at θ∼330–380 K near 40 N in May 1995, indicating the influence of intrusions of tropospheric air. Assuming that observed tracer‐tracer relationships reflect mixing lines between tropospheric and stratospheric air masses, we calculate mixing ratios of H2O (12–24 ppmv) and CO2 for the admixed tropospheric air at θ=352–364 K. Temperatures on the 355 K surface at 20–40 N were low enough to dehydrate air to these values. While most ER‐2 CO2 data in both hemispheres are consistent with tropical or subtropical air entering the lowermost stratosphere, measurements from May 1995 for θ<362 K suggest that entry of air from the midlatitude upper troposphere can occur in conjunction with mixing processes near the tropopause.

[1]  K. Mursula,et al.  Annual variation in near‐Earth solar wind speed: Evidence for persistent north‐south asymmetry related to solar magnetic polarity , 1998 .

[2]  James M. Russell,et al.  Hemispheric asymmetries in water vapor and inferences about transport in the lower stratosphere , 1997 .

[3]  J. Lelieveld,et al.  Chemical perturbation of the lowermost stratosphere through exchange with the troposphere , 1997 .

[4]  J. Lelieveld,et al.  In Situ Trace Gas and Particle Measurements in the Summer Lower Stratosphere during STREAM II: Implications for O3 Production , 1997 .

[5]  A. Tuck,et al.  The Brewer‐Dobson Circulation In the Light of High Altitude In Situ Aircraft Observations , 1997 .

[6]  S. Wofsy,et al.  Stratospheric Mean Ages and Transport Rates from Observations of Carbon Dioxide and Nitrous Oxide , 1996, Science.

[7]  C. Appenzeller,et al.  Ozone and potential vorticity at the subtropical tropopause break , 1996 .

[8]  Andrew J. Heymsfield,et al.  Stratosphere‐troposphere exchange in a midlatitude mesoscale convective complex: 1. Observations , 1996 .

[9]  E. Weinstock,et al.  Mechanisms controlling water vapor in the lower stratosphere: “A tale of two stratospheres” , 1995 .

[10]  J. Holton,et al.  Stratosphere‐troposphere exchange , 1995 .

[11]  Ping Chen.  Isentropic cross‐tropopause mass exchange in the extratropics , 1995 .

[12]  H. Yang,et al.  Production of Dry Air by Isentropic Mixing , 1994 .

[13]  M. Loewenstein,et al.  SPADE H2O measurements and the seasonal cycle of stratospheric water vapor , 1994 .

[14]  S. Wofsy,et al.  Tracer‐tracer relationships and lower stratospheric dynamics: CO2 and N2O correlations during SPADE , 1994 .

[15]  E. Weinstock,et al.  New fast response photofragment fluorescence hygrometer for use on the NASA ER‐2 and the Perseus remotely piloted aircraft , 1994 .

[16]  M. Loewenstein,et al.  Airborne tunable diode laser spectrometer for trace-gas measurement in the lower stratosphere. , 1993, Applied optics.

[17]  K. Rosenlof,et al.  Estimates of the stratospheric residual circulation using the downward control principle , 1993 .

[18]  H. Selkirk,et al.  Air mass origins and troposphere‐to‐stratosphere exchange associated with mid‐latitude cyclogenesis and tropopause folding inferred from 7Be measurements , 1991 .

[19]  Takakiyo Nakazawa,et al.  Temporal and spatial variations of upper tropospheric and lower stratospheric carbon dioxide , 1991 .

[20]  K.,et al.  The Meteorological Measurement System on the NASA ER-2 Aircraft , 1990 .

[21]  Gary S. Parks,et al.  Instrument description of the airborne microwave temperature profiler , 1989 .

[22]  M. Proffitt,et al.  Fast‐response dual‐beam UV‐absorption ozone photometer suitable for use on stratospheric balloons , 1983 .

[23]  A. W. Brewer.  Evidence for a world circulation provided by the measurements of helium and water vapour distribution in the stratosphere , 1949 .