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• 1. [Article] Seasonal variations of water vapor in the tropical lower stratosphere

  Measurements of stratospheric water vapor by the Microwave Limb Sounder aboard the Upper Atmosphere Research Satellite show that in the tropical lower stratosphere, low-frequency variations are closely related ...

  Citation × Citation Citation Abstract Copy Title: Seasonal variations of water vapor in the tropical lower stratosphere Author: Harwood, Robert S., Waters, Joe W., Holton, James R., Rosenloh, Karen H., Mote, Philip W. Measurements of stratospheric water vapor by the Microwave Limb Sounder aboard the Upper Atmosphere Research Satellite show that in the tropical lower stratosphere, low-frequency variations are closely related to the annual cycle in tropical tropopause temperatures. Tropical stratospheric air appears to retain information about the tropopause conditions it encountered for over a year as it rises through the stratosphere. We use a two-dimensional Lagrangian model to relate MLS measurements to the temperature that tropical air parcels encountered when crossing the 100 hPa surface. Title: Seasonal variations of water vapor in the tropical lower stratosphere Author: Harwood, Robert S., Waters, Joe W., Holton, James R., Rosenloh, Karen H., Mote, Philip W. Measurements of stratospheric water vapor by the Microwave Limb Sounder aboard the Upper Atmosphere Research Satellite show that in the tropical lower stratosphere, low-frequency variations are closely related to the annual cycle in tropical tropopause temperatures. Tropical stratospheric air appears to retain information about the tropopause conditions it encountered for over a year as it rises through the stratosphere. We use a two-dimensional Lagrangian model to relate MLS measurements to the temperature that tropical air parcels encountered when crossing the 100 hPa surface. Close

• 2. [Article] An atmospheric tape recorder: the imprint of tropical tropopause temperatures on stratospheric water vapor

  Citation × Citation Citation Abstract Copy Title: An atmospheric tape recorder: the imprint of tropical tropopause temperatures on stratospheric water vapor Author: Mote, Philip W., Waters, Joe W., Pumphrey, Hugh C., Kinnersley, Jonathan S., Russell, James M., Carr, Ewan S, Rosenlof, Karen H., McIntyre, Michael E., Gille, John C., Holton, James R. Title: An atmospheric tape recorder: the imprint of tropical tropopause temperatures on stratospheric water vapor Author: Mote, Philip W., Waters, Joe W., Pumphrey, Hugh C., Kinnersley, Jonathan S., Russell, James M., Carr, Ewan S, Rosenlof, Karen H., McIntyre, Michael E., Gille, John C., Holton, James R. Close

• 3. [Article] Characteristics of stratosphere-troposphere exchange in a general circulation model

  Air and trace gases are exchanged between the stratosphere and the troposphere on a variety of scales; but general circulation models (GCMs) are unable to represent the smaller scales. It would be useful ...

  Citation × Citation Citation Abstract Copy Title: Characteristics of stratosphere-troposphere exchange in a general circulation model Author: Mote, Philip W., Holton, James R., Boville, Byron A. Air and trace gases are exchanged between the stratosphere and the troposphere on a variety of scales; but general circulation models (GCMs) are unable to represent the smaller scales. It would be useful to see how a GCM represents stratosphere-troposphere exchange (STE), both to identify possible model deficiencies which would affect other studies and to see how important the smaller-scale physics might be in the atmosphere itself. Our understanding of observed STE depends largely on inferences from tracer distributions. In this study we examine mass exchange, water vapor exchange, and the behavior of idealized tracers and parcels to diagnose STE in the National Center for Atmospheric Research GCM, the Community Climate Model (CCM2). The CCM2 correctly represents the seasonality of mass exchange across 100 hPa, but values are uniformly too strong. Water vapor, however, indicates that tropical STE is not well represented in the CCM2; even though mean tropopause temperatures are colder than observed, the lower stratosphere is too moist. Most net mass flux occurs at water vapor mixing ratios of about 4-5 parts per million by volume (ppmv), about 1 ppmv too moist. Vertical resolution has little impact on the nature of tropical STE. In midlatitudes, CCM2 more successfully represents STE, which occurs in developing baroclinic waves and stationary anticyclones. Exchange from troposphere to stratosphere does occur but only influences the lowest few kilometers of the extratropical stratosphere, even for tracers with large vertical gradients Title: Characteristics of stratosphere-troposphere exchange in a general circulation model Author: Mote, Philip W., Holton, James R., Boville, Byron A. Air and trace gases are exchanged between the stratosphere and the troposphere on a variety of scales; but general circulation models (GCMs) are unable to represent the smaller scales. It would be useful to see how a GCM represents stratosphere-troposphere exchange (STE), both to identify possible model deficiencies which would affect other studies and to see how important the smaller-scale physics might be in the atmosphere itself. Our understanding of observed STE depends largely on inferences from tracer distributions. In this study we examine mass exchange, water vapor exchange, and the behavior of idealized tracers and parcels to diagnose STE in the National Center for Atmospheric Research GCM, the Community Climate Model (CCM2). The CCM2 correctly represents the seasonality of mass exchange across 100 hPa, but values are uniformly too strong. Water vapor, however, indicates that tropical STE is not well represented in the CCM2; even though mean tropopause temperatures are colder than observed, the lower stratosphere is too moist. Most net mass flux occurs at water vapor mixing ratios of about 4-5 parts per million by volume (ppmv), about 1 ppmv too moist. Vertical resolution has little impact on the nature of tropical STE. In midlatitudes, CCM2 more successfully represents STE, which occurs in developing baroclinic waves and stationary anticyclones. Exchange from troposphere to stratosphere does occur but only influences the lowest few kilometers of the extratropical stratosphere, even for tracers with large vertical gradients Close