Analysis and Modeling of Stratospheric Gravity Wave Activity Along ER-2 Flight Tracks

Abstract

Small-scale fluctuations in winds and temperatures are routinely encountered in-flight by the Meteorological Measurement System (MMS) on NASA's instrumented ER-2 stratospheric research aircraft. Recently, Bacmeister et al. (1996) demonstrated that the mean along-track autospectra of these fluctuations, as compiled from over 70 long-term flights from many different geographical regions, were largely consistent with a model spectrum of gravity waves which is separable in vertical wavenumber and intrinsic frequency. However, these stratospheric gravity-wave fluctuations also exhibit appreciable variations in intensity during many of these flights. In several cases, strong bursts of activity have been attributed to encounters with mountain lee waves which have propagated to ER-2 cruise altitudes of approx. 20 km (e.g., Bacmeister et al., 1990; Chan et al., 1993), while tropical flights have found bursts of activity when there was strong tropospheric convection beneath the aircraft (Alexander and Pfister, 1995). To study mountain-wave influences on bursts of activity in ER-2 data more systematically, Bacmeister et al. (1994) developed an operational model for forecasting mountain-wave activity and turbulence intensities in the stratosphere. It used detailed maps of topographic elevation (5'x5' resolution) together with National Center for Environmental Prediction (NCEP) forecast winds and temperatures to predict the forcing of waves by the forecast flow over topographic ridges in any region of interest. It then used a simple hydrostatic model of mountain wave propagation and breakdown within the forecast environment to predict whether these waves propagated into the stratosphere and/or produced turbulence.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1996
Accession Number
ADA531105

Entities

People

  • Crispin J. Marks
  • Julio T. Bacmeister
  • Stephen D. Eckermann

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aircrafts
  • Amplitude
  • Flight
  • Flight Paths
  • Gravity
  • Gravity Waves
  • Information Operations
  • Military Research
  • Mountains
  • New Zealand
  • Ray Tracing
  • Research Aircraft
  • Ridges
  • Turbulence
  • Two Dimensional
  • Wave Propagation
  • Waves

Fields of Study

  • Environmental science

Readers

  • Ocean-Atmosphere Mesoscale Modeling, Data Assimilation, and Flux Boundary Layers
  • Space Exploration and Orbital Mechanics.

Technology Areas

  • Space