490 research outputs found
Variability in upwelling across the tropical tropopause and correlations with tracers in the lower stratosphere
Temporal variability of the upwelling near the tropical tropopause on daily to annual timescales is investigated using three different estimates computed from the ERA-Interim reanalysis. These include upwelling archived by the reanalysis, plus estimates derived from thermodynamic and momentum balance calculations. Substantial variability in upwelling is observed on both seasonal and sub-seasonal timescales, and the three estimates show reasonably good agreement. Tropical upwelling should exert strong influence on temperatures and on tracers with large vertical gradients in the lower stratosphere. We test this behavior by comparing the calculated upwelling estimates with observed temperatures in the tropical lower stratosphere, and with measurements of ozone and carbon monoxide (CO) from the Aura Microwave Limb Sounder (MLS) satellite instrument. Time series of temperature, ozone and CO are well correlated in the tropical lower stratosphere, and we quantify the influence of tropical upwelling on this joint variability. Strong coherent annual cycles observed in each quantity are found to reflect the seasonal cycle in upwelling. Statistically significant correlations between upwelling, temperatures and tracers are also found for sub-seasonal timescales, demonstrating the importance of upwelling in forcing transient variability in the lower tropical stratosphere
Influence of Season of Birth on Reproductive Development of Brahman Bulls
Last updated: 6/12/200
Effects of Dietary Rice Bran, Lasalocid, and Sex of Calf on Postpartum Reproduction in Brahman Cows
Last updated: 6/12/200
Thermal structure of intense convective clouds derived from GPS radio occultations
Thermal structure associated with deep convective clouds is investigated using Global Positioning System (GPS) radio occultation measurements. GPS data are insensitive to the presence of clouds, and provide high vertical resolution and high accuracy measurements to identify associated temperature behavior. Deep convective systems are identified using International Satellite Cloud Climatology Project (ISCCP) satellite data, and cloud tops are accurately measured using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) lidar observations; we focus on 53 cases of near-coincident GPS occultations with CALIPSO profiles over deep convection. Results show a sharp spike in GPS bending angle highly correlated to the top of the clouds, corresponding to anomalously cold temperatures within the clouds. Above the clouds the temperatures return to background conditions, and there is a strong inversion at cloud top. For cloud tops below 14 km, the temperature lapse rate within the cloud often approaches a moist adiabat, consistent with rapid undiluted ascent within the convective systems
Effect of cottonseed meal consumption on performance of female fallow deer
Last updated: 6/12/200
Consuming Whole Cottonseed Affects Growth and Reproduction of Male Cervids
Last updated: 6/12/200
Trajectory model simulations of ozone (O<sub>3</sub>) and carbon monoxide (CO) in the lower stratosphere
A domain-filling, forward trajectory model originally developed for
simulating stratospheric water vapor is used to simulate ozone (O3) and
carbon monoxide (CO) in the lower stratosphere. Trajectories are
initialized in the upper troposphere, and the circulation is based on
reanalysis wind fields. In addition, chemical production and loss rates
along trajectories are included using calculations from the Whole Atmosphere
Community Climate Model (WACCM). The trajectory model results show good
overall agreement with satellite observations from the Aura Microwave Limb
Sounder (MLS) and the Atmospheric Chemistry Experiment Fourier Transform
Spectrometer (ACE-FTS) in terms of spatial structure and seasonal
variability. The trajectory model results also agree well with the Eulerian
WACCM simulations. Analysis of the simulated tracers shows that seasonal
variations in tropical upwelling exerts strong influence on O3 and CO
in the tropical lower stratosphere, and the coupled seasonal cycles provide
a useful test of the transport simulations. Interannual variations in the
tracers are also closely coupled to changes in upwelling, and the trajectory
model can accurately capture and explain observed changes during 2005–2011.
This demonstrates the importance of variability in tropical upwelling in
forcing chemical changes in the tropical lower stratosphere
Comparison of Traits at Sexual Maturity of Recently Introduced Breeds to Angus and Brahman Bulls
Last updated: 6/12/200
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