Internal gravity wave selection in the upper troposphere and lower stratosphere observed by the MU radar: Preliminary results

1989 ◽  
Vol 130 (2-3) ◽  
pp. 481-495 ◽  
Author(s):  
Manabu D. Yamanaka ◽  
Shoichiro Fukao ◽  
Hiromasa Matsumoto ◽  
Toru Sato ◽  
Toshitaka Tsuda ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Lower Stratosphere ◽  
Internal Gravity Wave ◽  
Upper Troposphere ◽  
Preliminary Results ◽  
Mu Radar

Internal Gravity Wave Selection in the Upper Troposphere and Lower Stratosphere Observed by the MU Radar: Preliminary Results

1989 ◽  
pp. 481-495 ◽  
Author(s):  
Manabu D. Yamanaka ◽  
Shoichiro Fukao ◽  
Hiromasa Matsumoto ◽  
Toru Sato ◽  
Toshitaka Tsuda ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Lower Stratosphere ◽  
Internal Gravity Wave ◽  
Upper Troposphere ◽  
Preliminary Results ◽  
Mu Radar

scholarly journals Analysis of internal gravity waves with GPS RO density profiles

2014 ◽  
Vol 7 (12) ◽  
pp. 4123-4132 ◽  
Author(s):  
P. Šácha ◽  
U. Foelsche ◽  
P. Pišoft
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Internal Gravity Wave ◽  
Internal Gravity Waves ◽  
Atmospheric Density ◽  
Retrieval Process ◽  
Density Profiles ◽  
Height Range ◽  
Upper Troposphere ◽  
The Past

Abstract. GPS radio occultation (RO) data have proved to be a great tool for atmospheric monitoring and studies. In the past decade, they were frequently used for analyses of the internal gravity waves in the upper troposphere and lower stratosphere region. Atmospheric density is the first quantity of state gained in the retrieval process and is not burdened by additional assumptions. However, there are no studies elaborating in detail the utilization of GPS RO density profiles for gravity wave analyses. In this paper, we introduce a method for density background separation and a methodology for internal gravity wave analysis using the density profiles. Various background choices are discussed and the correspondence between analytical forms of the density and temperature background profiles is examined. In the stratosphere, a comparison between the power spectrum of normalized density and normalized dry temperature fluctuations confirms the suitability of the density profiles' utilization. In the height range of 8–40 km, results of the continuous wavelet transform are presented and discussed. Finally, the limits of our approach are discussed and the advantages of the density usage are listed.

scholarly journals On the Development of Above-Anvil Cirrus Plumes in Extratropical Convection

2017 ◽  
Vol 74 (5) ◽  
pp. 1617-1633 ◽  
Author(s):  
Cameron R. Homeyer ◽  
Joel D. McAuliffe ◽  
Kristopher M. Bedka
Keyword(s):  
Gravity Wave ◽  
Wave Breaking ◽  
Lower Stratosphere ◽  
Atmospheric Conditions ◽  
Upper Troposphere ◽  
Using Data ◽  
The Stability ◽  
Anvil Cirrus ◽  
Cloud Material ◽  
Relative Wind

Abstract Expansive cirrus clouds present above the anvils of extratropical convection have been observed in satellite and aircraft-based imagery for several decades. Despite knowledge of their occurrence, the precise mechanisms and atmospheric conditions leading to their formation and maintenance are not entirely known. Here, the formation of these cirrus “plumes” is examined using a combination of satellite imagery, four-dimensional ground-based radar observations, assimilated atmospheric states from a state-of-the-art reanalysis, and idealized numerical simulations with explicitly resolved convection. Using data from 20 recent events (2013–present), it is found that convective cores of storms with above-anvil cirrus plumes reach altitudes 1–6 km above the tropopause. Thus, it is likely that these clouds represent the injection of cloud material into the lower stratosphere. Comparison of storms with above-anvil cirrus plumes and observed tropopause-penetrating convection without plumes reveals an association with large vector differences between the motion of a storm and the environmental wind in the upper troposphere and lower stratosphere (UTLS), suggesting that gravity wave breaking and/or stretching of the tropopause-penetrating cloud are/is more prevalent in plume-producing storms. A weak relationship is found between plume occurrence and the stability of the lower stratosphere (or tropopause structure), and no relationship is found with the duration of stratospheric penetration or stratospheric humidity. Idealized model simulations of tropopause-penetrating convection with small and large magnitudes of storm-relative wind in the UTLS are found to reproduce the observationally established storm-relative wind relationship and show that frequent gravity wave breaking is the primary mechanism responsible for plume formation.

scholarly journals Eddy Diffusivities for Momentum and Heat in the Upper Troposphere and Lower Stratosphere Measured by MU Radar and RASS, and a Comparison of Turbulence Model Predictions

2012 ◽  
Vol 69 (1) ◽  
pp. 323-337 ◽  
Author(s):  
Hiromasa Ueda ◽  
Tetsuo Fukui ◽  
Mizuo Kajino ◽  
Mitsuaki Horiguchi ◽  
Hiroyuki Hashiguchi ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Lower Stratosphere ◽  
Spectral Width ◽  
Eddy Diffusivity ◽  
Stress Model ◽  
Upper Troposphere ◽  
Algebraic Stress Model ◽  
Eddy Diffusivities ◽  
Mu Radar ◽  
Order Of Magnitude

Abstract Recently, middle- and upper-atmosphere Doppler radar (MU radar) has enabled the measurement of middle-atmosphere turbulence from radar backscatter Doppler spectra. In this work, eddy diffusivities for momentum Km in the upper troposphere and lower stratosphere during clear-air conditions were derived from direct measurements of the Reynolds stress and vertical gradient of mean wind velocity measured by MU radar. Eddy diffusivity for heat Kh below 8 km was determined from measurements of temperature fluctuations by the Radio Acoustic Sounding System (RASS) attached to the MU radar. The eddy diffusivity for momentum was on the order of 10 m2 s−1 in the upper troposphere and decreased gradually in the stratosphere by an order of magnitude or more. The eddy diffusivity for heat was almost of the same order of magnitude as Km. Estimates of eddy diffusivity from the radar echo power spectral width give fairly good values compared with the direct measurement of Km. Applicability of three turbulence models—the spectral width method, the k–ɛ model modified for stratified flows, and the algebraic stress model—were also examined, using radar observation values of turbulent kinetic energy k and turbulent energy dissipation rate ɛ together with atmospheric stability observations from rawinsonde data. It is concluded that the algebraic stress model shows the best fit with the direct measurement of Km, even in the free atmosphere above the atmospheric boundary layer once k and ɛ values are obtained from observations or a model.

scholarly journals Mixing Layer Formation near the Tropopause Due to Gravity Wave–Critical Level Interactions in a Cloud-Resolving Model

2004 ◽  
Vol 61 (24) ◽  
pp. 3112-3124 ◽  
Author(s):  
Mohamed Moustaoui ◽  
Binson Joseph ◽  
Hector Teitelbaum
Keyword(s):  
Gravity Wave ◽  
Lower Stratosphere ◽  
Critical Level ◽  
Mixing Layer ◽  
Mixing Layers ◽  
Upper Troposphere ◽  
Cloud Resolving Model ◽  
Tropopause Region ◽  
Plausible Mechanism

Abstract A plausible mechanism for the formation of mixing layers in the lower stratosphere above regions of tropical convection is demonstrated numerically using high-resolution, two-dimensional (2D), anelastic, nonlinear, cloud-resolving simulations. One noteworthy point is that the mixing layer simulated in this study is free of anvil clouds and well above the cloud anvil top located in the upper troposphere. Hence, the present mechanism is complementary to the well-known process by which overshooting cloud turrets causes mixing within stratospheric anvil clouds. The paper is organized as a case study verifying the proposed mechanism using atmospheric soundings obtained during the Central Equatorial Pacific Experiment (CEPEX), when several such mixing layers, devoid of anvil clouds, had been observed. The basic dynamical ingredient of the present mechanism is (quasi stationary) gravity wave–critical level interactions, occurring in association with a reversal of stratospheric westerlies to easterlies below the tropopause region. The robustness of the results is shown through simulations at different resolutions. The insensitivity of the qualitative results to the details of the subgrid scheme is also evinced through further simulations with and without subgrid mixing terms. From Lagrangian reconstruction of (passive) ozone fields, it is shown that the mixing layer is formed kinematically through advection by the resolved-scale (nonlinear) velocity field.

scholarly journals A Case Study of Mass Transport during the East-West Oscillation of the Asian Summer Monsoon Anticyclone

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Jiali Luo ◽  
Jiayao Song ◽  
Hongying Tian ◽  
Lei Liu ◽  
Xinlei Liang
Keyword(s):  
Lower Stratosphere ◽  
Asian Summer Monsoon ◽  
Chemical Transport ◽  
Upward Motion ◽  
High Concentration ◽  
Upper Troposphere ◽  
Asian Summer ◽  
Mode Tm ◽  
East West

We use ERA-Interim reanalysis, MLS observations, and a trajectory model to examine the chemical transport and tracers distribution in the Upper Troposphere and Lower Stratosphere (UTLS) associated with an east-west oscillation case of the anticyclone in 2016. The results show that the spatial distribution of water vapor (H2O) was more consistent with the location of the anticyclone than carbon monoxide (CO) at 100 hPa, and an independent relative high concentration center was only found in H2O field. At 215 hPa, although the anticyclone center also migrated from the Tibetan Mode (TM) to the Iranian Mode (IM), the relative high concentration centers of both tracers were always colocated with regions where upward motion was strong in the UTLS. When the anticyclone migrated from the TM, air within the anticyclone over Tibetan Plateau may transport both westward and eastward but was always within the UTLS. The relative high concentration of tropospheric tracers within the anticyclone in the IM was from the east and transported by the westward propagation of the anticyclone rather than being lifted from surface directly. Air within the relative high geopotential height centers over Western Pacific was partly from the main anticyclone and partly from lower levels.

Atmospheric measurements of aerosol precursor gases in the upper troposphere and lower stratosphere

1997 ◽  
Vol 28 ◽  
pp. S65-S66 ◽  
Author(s):  
F. Arnold ◽  
K.H. Wohlfrom ◽  
J. Schneider ◽  
M. Klemm ◽  
T. Stilp ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Atmospheric Measurements ◽  
Upper Troposphere
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