نتایج جستجو برای: troposphere
تعداد نتایج: 5309 فیلتر نتایج به سال:
Light scattering measurements from a searchlight beam were carried out in New Mexico to determine the aerosol properties of the atmosphere. Although data were acquired to an altitude of about 70 km, the results show the aerosol attenuation parameters to be significant to about 35 km. The expression for the aerosol attenuation coefficient is derived based on the field geometry in conjunction wit...
During June, July and August 2006 five aircraft took part in a campaign over West Africa to observe the aerosol content and chemical composition of the troposphere and lower stratosphere as part of the African Monsoon Multidisciplinary Analysis (AMMA) project. These are the first such measurements in this region during the monsoon period. In addition to providing an overview of the tropospheric...
This study evaluates the ability of the Community Multiscale Air Quality (CMAQ) model to simulate the spatial variability of summertime ozone (O3) at the surface and in the free troposphere over the continental United States. Simulated surface O3 concentrations are compared with 987 Air Quality System (AQS) sites and 123 Clean Air Status and Trends Network (CASTNet) sites. CMAQ’s ability to rep...
We assessed the sensitivity of regional CO source estimates to the modeled vertical CO distribution by assimilating multi-spectral MOPITT (Measurements of Pollution In The Troposphere) V5J CO retrievals with the GEOSChem model. We compared the source estimates obtained by assimilating the CO profiles and the surface layer retrievals from June 2004 to May 2005. Because the surface layer retrieva...
Understanding the development and variation of the atmospheric circulation regimes driven by the Atlantic multidecadal oscillation (AMO) is essential because these circulations interact with other forcings on decadal and interannual time scales. Collectively, they determine the summer (June, July, and August) precipitation variations for North America. In this study, a general circulation model...
The stratosphere-troposphere (ST) mode operation of the Indian mesospherestratosphere-troposphere (MST) radar provided evidence of multiple stable layer slxucmres near the tropopause and also of its "weakening" during late night hours on several occasions. Mass exchange can take place between the troposphere and the stratosphere during periods of such weakening. To examine whether there is any ...
We present the configuration of the Météo-France Chemistry and Transport Model (CTM) MOCAGE-Climat that will be dedicated to the study of chemistry and climate interactions. MOCAGE-Climat is a state-of-the-art CTM that simulates the global distribution of ozone and its precursors (82 chemical species) both in the troposphere and the stratosphere, up to the mid-mesosphere (∼70 km). Surface proce...
Using the ERA5 reanalysis data and trajectory analysis provided by Hysplit4, a comparative was conducted on primary pathways of air particles dominant weather systems in two distinct cases equatorward poleward cyclonic Rossby wave-breaking (CWB) events. Subsequently, characteristics mass exchange between stratosphere troposphere both CWBs were estimated discussed. CWB events are frequently asso...
The Mediterranean troposphere exhibits a marked and localised summertime ozone maximum, which has the potential to strongly impact regional air quality and radiative forcing. The Mediterranean region can be perturbed by long-range pollution import from Northern Europe, North America and Asia, in addition to local emissions, which may all contribute to regional ozone enhancements. We exploit ozo...
[1] Estimates of surface fluxes of carbon monoxide (CO) inferred from remote sensing observations or free tropospheric trace gas measurements using global chemical transport models can have significant uncertainties because of discrepancies in the vertical transport in the models, which make it challenging to unequivocally relate the observations back to the surface fluxes in the models. The ne...
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