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Satellite-Derived Climatology Products for Monitoring Convection Over West and Central Africa
A weather forecaster’s knowledge of climatology is important to the success of a forecast, especially where convection is involved. That’s particularly true over Central and West Africa where convection has a strong diurnal cycle and usually develops over particular geographic regions and during specific time intervals. The lesson describes satellite-derived cloud climatology products and several global instability indices, all of which can be integrated with other products to forecast convection. Although the lesson uses examples of climatology products from specific months, it makes the full ...
Weather Observing Fundamentals
"Weather Observing Fundamentals" provides guidance for U.S. Navy Aerographer's Mates, Quartermasters, and civilian observers tasked with taking and reporting routine, special, and synoptic observations. Although the focus of this lesson is on shipboard observations, much of the content applies to land-based observing and reporting as well. The lesson details standard procedures for taking accurate weather observations and for encoding those observations on COMNAVMETOCCOM Report 3141/3. Exercises throughout the lesson and four weather identification drills at the end provide learners with oppor ...
Writing TAFs for Ceilings and Visibility, Africa Edition
Writing TAFs for Ceilings and Visibility, Africa Edition outlines the processes for developing an effective Terminal Aerodrome Forecast (TAF) that meets International Civil Aviation Organization (ICAO) guidelines. Geared specifically to forecasters in Africa, the lesson includes a case study for an event impacting Cape Town International Airport to provide practice applying the processes to real-life forecast situations.
WWRP, 2012-1. Recommended Methods for Evaluating Cloud and Related Parameters
World Meteorological Organization (WMO) ; WWRP/WGNE Joint Working Group on Forecast Verification Research (JWGFVR) - WMO, 2012Cloud errors can have wide-reaching impacts on the accuracy and quality of outcomes, most notably, but not exclusively, on temperature. This is especially true for weather forecasting, where cloud cover has a significant impact on human comfort and wellbeing. Whilst public perception may not be interested in absolute precision, i.e. whether there were 3 or 5 okta of cloud, there is anecdotal evidence to suggest strong links between the perceptions of overall forecast accuracy and whether the cloud was forecast correctly, mostly because temperature errors often go hand-in-hand. It is therefore ...
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Microphysical and radiative effects of aerosols on warm clouds during the Amazon biomass burning season as observed by MODIS: impacts of water vapor and land cover
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 7. Ten Hoeve J.E.; Remer L.A.; Jacobson M.Z. - Copernicus GmbH, 2011Aerosol, cloud, water vapor, and temperature profile data from the Moderate Resolution Imaging Spectroradiometer (MODIS) are utilized to examine the impact of aerosols on clouds during the Amazonian biomass burning season in Rondônia, Brazil. It is found that increasing background column water vapor (CWV) throughout this transition season between the Amazon dry and wet seasons likely exerts a strong effect on cloud properties. As a result, proper analysis of aerosol-cloud relationships requires that data be stratified by CWV to account better for the influence of background meteorological vari ...
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The 2009–2010 Arctic polar stratospheric cloud season: a CALIPSO perspective
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 5. Pitts M.C.; Poole L.R.; Dörnbrack A.; et al. - Copernicus GmbH, 2011Spaceborne lidar measurements from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) are used to provide a vortex-wide perspective of the 2009–2010 Arctic PSC (polar stratospheric cloud) season to complement more focused measurements from the European Union RECONCILE (reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) field campaign. The 2009–2010 Arctic winter was unusually cold at stratospheric levels from mid-December 2009 until the end of January 2010, and was one of only ...
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Dependence of aerosol-precipitation interactions on humidity in a multiple-cloud system
This study examines the dependence of aerosol-precipitation interactions on environmental humidity in a mesoscale cloud ensemble (MCE) which is composed of convective and stratiform clouds. The author found that increases in aerosol concentration enhance evaporative cooling, which raises not only the intensity of vorticity and entrainment but also that of downdrafts and low-level convergence. The increase in vorticity tends to suppress precipitation. The increase in low-level convergence tends to enhance precipitation by generating more secondary clouds in a muptiple-cloud system simulated her ...
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Characteristics, sources, and transport of aerosols measured in spring 2008 during the aerosol, radiation, and cloud processes affecting Arctic Climate (ARCPAC) Project
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Brock C.A.; Cozic J.; Bahreini R.; et al. - Copernicus GmbH, 2011We present an overview of the background, scientific goals, and execution of the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project of April 2008. We then summarize airborne measurements, made in the troposphere of the Alaskan Arctic, of aerosol particle size distributions, composition, and optical properties and discuss the sources and transport of the aerosols. The aerosol data were grouped into four categories based on gas-phase composition. First, the background troposphere contained a relatively diffuse, sulfate-rich aerosol extending from the top of the sea ...
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Optical properties of pristine ice crystals in mid-latitude cirrus clouds: a case study during CIRCLE-2 experiment
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Gayet J.-F.; Mioche G.; Shcherbakov V.; et al. - Copernicus GmbH, 2011In this paper, we describe in situ observations of mid-latitude cirrus cloud band carried out on 16 May 2007 during the CIRCLE-2 experiment. The Polar Nephelometer and the Cloud Particle Imager (CPI) instruments with PMS FSSP-300 and 2D-C probes were used for the description of the optical and microphysical cloud properties. Two selected cloud regions are compared and discussed in detail. Significant differences in optical properties are evidenced in terms of 22° halo occurrences even though prevalent planar-plate ice crystals are observed in both cloud regions. Featureless scattering phase fu ...
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Evaluating the effects of microphysical complexity in idealised simulations of trade wind cumulus using the Factorial Method
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Dearden C.; Connolly P.J.; Choularton T.W.; et al. - Copernicus GmbH, 2011The effect of microphysical and environmental factors on the development of precipitation in warm idealised cloud is explored using a kinematic modelling framework. A simple one-dimensional column model is used to drive a suite of microphysics schemes including a flexible multi-moment bulk scheme (including both single and dual moment cloud liquid water) and a state-of-the-art bin-resolved scheme with explicit treatments of liquid and aerosol. The Factorial Method is employed to quantify and compare the sensitivities of each scheme under a set of controlled conditions, in order to isolate the ...
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Scale-by-scale analysis of probability distributions for global MODIS-AQUA cloud properties: how the large scale signature of turbulence may impact statistical analyses of clouds
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. de la Torre Juárez M.; Davis A.B.; Fetzer E.J. - Copernicus GmbH, 2011Means, standard deviations, homogeneity parameters used in models based on their ratio, and the probability distribution functions (PDFs) of cloud properties from the MODerate resolution Infrared Spectrometer (MODIS) are estimated globally as function of averaging scale varying from 5 to 500 km. The properties – cloud fraction, droplet effective radius, and liquid water path – all matter for cloud-climate uncertainty quantification and reduction efforts. Global means and standard deviations are confirmed to change with scale. For the range of scales considered, global means vary only within 3% ...
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Chemical composition and mixing-state of ice residuals sampled within mixed phase clouds
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Ebert M.; Worringen A.; Benker N.; et al. - Copernicus GmbH, 2011During an intensive campaign at the high alpine research station Jungfraujoch, Switzerland, in February/March 2006 ice particle residuals within mixed-phase clouds were sampled using the Ice-counterflow virtual impactor (Ice-CVI). Size, morphology, chemical composition, mineralogy and mixing state of the ice residual and the interstitial (i.e., non-activated) aerosol particles were analyzed by scanning and transmission electron microscopy. Ice nuclei (IN) were identified from the significant enrichment of particle groups in the ice residual (IR) samples relative to the interstitial aerosol. In ...
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On the impacts of phytoplankton-derived organic matter on the properties of the primary marine aerosol – Part 2: Composition, hygroscopicity and cloud condensation activity
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Fuentes E.; Coe H.; Green D.; et al. - Copernicus GmbH, 2011The effect of nanogel colloidal and dissolved organic matter <0.2 μm, secreted by marine biota, on the hygroscopic growth and droplet activation behaviour of the primary marine aerosol was studied. Seawater proxies were prepared by the combination of artificial seawater devoid of marine organics and natural seawater enriched in organic exudate released by laboratory-grown phytoplankton cultures, as described in a companion paper. The primary aerosol was produced by bubble bursting, using a plunging multijet system as an aerosol generator.
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Cloud condensation nuclei in polluted air and biomass burning smoke near the mega-city Guangzhou, China – Part 2: Size-resolved aerosol chemical composition, diurnal cycles, and externally mixed weakly CCN-active soot particles
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Rose D.; Gunthe S.S.; Su H.; et al. - Copernicus GmbH, 2011Size-resolved chemical composition, mixing state, and cloud condensation nucleus (CCN) activity of aerosol particles in polluted mega-city air and biomass burning smoke were measured during the PRIDE-PRD2006 campaign near Guangzhou, China, using an aerosol mass spectrometer (AMS), a volatility tandem differential mobility analyzer (VTDMA), and a continuous-flow CCN counter (DMT-CCNC).
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