Oceanography and Atmospheric Sciences and Meteorology Commons^™

Analysis Of The Ttl Cirrus And Their Convective Origin - A Water Perspective, Tao Wang, Andrew Dessler

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

Two mechanisms are thought to be primarily responsible for the formation of cirrus in the Tropical Tropopause Layer (TTL): detrainment from deep convective anvils and in situ initiation. By analyzing water vapor measurements from the Aura Microwave Limb Sounder (MLS) and ice water content measurements from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), we identify TTL cirrus that contain too much ice to have been formed in situ—and therefore must be of convective origin. Analyzing 3 years of CALIPSO measurements (2008–2010), we found three maxima in the occurrence of convective cirrus: equatorial Africa, the tropical western Pacific, and …

The Representation Of The Ttl In A Tropical Channel Version Of Wrf Model, Stephanie Evan

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

In this study, the Weather Research Forecast (WRF) model is used to investigate key physical processes controlling the Tropical Tropopause Layer (TTL) temperature and water vapor distributions in December-January-February (DJF) 2006. The model domain is configured as a tropical channel with a horizontal grid-spacing of 37 km, a vertical grid-spacing of 500 m and a top at 0.1 hPa. Initial and boundary conditions are set using European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis Interim data. An ozone distribution computed from satellite and ozonesonde measurements is used for radiative forcing calculations.

The modelʼs ability to replicate observed TTL temperature variability …

Water Vapor And Cloud Formation In The Ttl: Simulation Results Vs. Satellite Observations, Tao Wang, Andrew Dessler, Mark Schoeberl

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

Driven by analyzed winds and temperature, domain-filling forward trajectory calculations are used to reproduce water vapor and cloud formations in the tropical tropopause layer (TTL). As with most Lagrangian models of this type, excess water vapor is instantaneously removed from the parcel to keep the relative humidity with respect to ice from exceeding a specified (super) saturation level. The dehydration occurrences serve as an indication of where and when cloud forms. Convective moistening through ice lofting and gravity waves are also included in our simulations as mechanisms that could affect water vapor abundances and cloud formations in the TTL. Our …

Constraining Middle Atmospheric Mositure In Geos-5 Using Eos-Mls Observations, Jianjun Jin

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

On The Turbulent Mixing And Ozone Variations Around The Tropical Tropopause Associated With Kelvin Waves, Kazunari Koishi

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

The observed variations of ozone around the tropical tropopause layer in relation to large-scale waves both in the altitude and isentropic coordinates were examined by analyzing ozonesondes provided by SHADOZ (Southern Hemisphere Additional Ozonesondes). Because ozone near this level can be used for the tracer of atmospheric motion, we regarded an ozone enhancement as the signal of a turbulent mixing. Focusing on the vertical fine structure of ozone and temperature, this study presents observed variations of 10 stations near the equator. Based on the signals of Kelvin waves (an eastward-traveling component of equatorial waves) which is filtered in the spectral-frequency …

Data Assimilation, Kazuyuki Miyazaki

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Simulations (Idealized To Global), Eric Jensen

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Satellite Observations, Masato Shiotani

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Ground Based Observations, Fumio Hasebe, Takashi Shibata

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

In-Situ Aircraft Observations, Karen Rosenlof

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Stratospheric Dynamics (Including Waves), Joan Alexander

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Trace Species And Chemistry (Besides Water), Anne Thompson

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Ttl Transport & Wave Processes, Masatomo Fujiwara

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Water Vapor, William Randel

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Cirrus Clouds And Convection In The Ttl, Leonard Pfister

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Ttl Overview And Radiative Transfer, Andrew Gettelman

U.S. - Japan Bilateral Workshop on the Tropical Tropopause Layer: State of the Current Science and Future Observational Needs

No abstract provided.

Shallow Water Flow Modeling Using Space-Time Least-Squares Finite-Element Method, Shin-Jye Liang, Chiung-Yang Lan, Ying-Chih Chen

Journal of Marine Science and Technology–Taiwan

Various aglogrithms of least-squares finite-element methods (LSFEM) for convection-diffusion equation (CDE) and shallow-water equations (SWE) are formulated. The associated condition number of the resulting system of equations is systematically compared. It is found that condition number of the resulting system of equations depends on the choice of variables, interpolations, and size of element (∆x). In general, a better conditioned system is obtained by introducing auxiliary variable with low-order interpolation. The developed better conditioned shallow-water model is used to simulate wave propagation over a submerged bar and wave propagation past an elliptical hump. Computed results are compared with experiment data and …

Design And Implementation Of An Simulation Of Water Wave Transformation Using Higher Order Mild-Slope Equation, Yuan-Jyh Lan, Tai-Wen Hsu, Ta-Yuan Lin, Shin-Jye Liang

Journal of Marine Science and Technology–Taiwan

A higher-order mild-slope equation (HOMSE) is derived based on theory of Hsu et al. [14]. Depth function is approximated up to third-order accurate in terms of both wave nonlinearity and bottom slope. Classical Galerkin method is used to solve HOMSE. Developed model is verified with a series of benchmark tests, including propagation of a sinusoidal wave past a submerged bar, wave propagating on a sloping bed, wave propagating over an elliptic shoal on a uniform slope, and wave propagating through a semicircular slope bottom, respectively. Computed results are compared with experiment data and prediction of low-order mild-slope equation model as …

Inverting Sediment Sound Speed Profile Using A Parameterized Geoacoustic Model: Numerical And Statistical Analysis, Chen-Fen Huang, Shih-Feng Yang, Jin-Yuan Liu

Journal of Marine Science and Technology–Taiwan

The objective of this paper is to develop and evaluate an inversion algorithm for estimating the parameters in a geoacoustic model for a marine sediment layer. The geoacoustic model employs a generalized-exponential function for sound speed profile, and an inverse-square function for density distribution. Based upon plane-wave reflection from a nonuniform sediment layer overlying an elastic seafloor, an inversion procedure is established and numerically implemented for estimating the parameters using synthetic noisecontaminated data. The sensitivity of each model parameter is first studied, and then three highly sensitive parameters in the geoacoustic model and one statistical parameter are chosen for inversion …

Electron Loss And Meteoric Dust In The Mesosphere, M. Friedrich, M. Rapp, T. Blix, U. P. Hoppe, K. Torkar, S. Robertson, S. Dickson, Kristina Lynch

Dartmouth Scholarship

No abstract provided.