Collection and analysis of radar rainfall and satellite data for the Darwin TRMM experiment

The following subject areas are covered: video cloud camera (purpose, design, operation, data); special observing periods (SOP-2, SOP 2.5 - an extension of SOP-2); Garand algorithm; and warm rain

Application of lightning data to satellite-based rainfall estimation

Information on lightning may improve rain estimates made from infrared images of a geostationary satellite. We address this proposition through a case from the Cooperative Huntsville Meteorological Experiment (COHMEX). During the afternoon and evening of 13 July 1986 waves of showers and thunderstorms developed over and near the lower Tennessee River Valley. For the shower and thunderstorm region within 200 km of the National Weather Service radar at Nashville, Tennessee, we measure cold-cloud area in a sequence of GOES infrared images covering all but the end of the shower and thunderstorm period. From observations of the NASA/Marshall direction-finding network in this small domain, we also count cloud-to-ground lightning flashes and, from scans of the Nashville radar, we calculate volume rain flux. Using a modified version of the Williams and Houze scheme, over an area within roughly 240 km of the radar (the large domain), we identify and track cold cloud systems. For these systems, over the large domain, we measure area and count flashes; over the small domain, we calculate volume rain flux. For a temperature threshold of 235K, peak cloud area over the small domain lags both peak rain flux and peak flash count by about four hours. At a threshold of 226K, the lag is about two hours. Flashes and flux are matched in phase. Over the large domain, nine storm systems occur. These range in size from 300 to 60,000 km(exp 2); in lifetime, from about 2 1/2 h to 6 h or more. Storm system area lags volume rain flux and flash count; nevertheless, it is linked with these variables. In essential respects the associations were the same when clouds were defined by a threshold of 226K. Tentatively, we conclude that flash counts complement infrared images in providing significant additional information on rain flux

The relationship of marine stratus to synoptic conditions

The marine stratus which persistently covered most of the eastern Pacific Ocean, had large clear areas during the FIRE Intensive Field Operations (IFO) in 1987. Clear zones formed inside the large oceanic cloud mass on almost every day during the IFO. The location and size of the clear zones varied from day to day implying that they were related to dynamic weather conditions and not to oceanic conditions. Forecasting of cloud cover for aircraft operations during the IFO was directed towards predicting when and where the clear and broken zones would form inside the large marine stratus cloud mass. The clear zones often formed to the northwest of the operations area and moved towards it. However, on some days the clear zones appeared to form during the day in the operations area as part of the diurnal cloud burn off. The movement of the clear zones from day to day were hard to follow because of the large diurnal changes in cloud cover. Clear and broken cloud zones formed during the day only to distort in shape and fill during the following night. The field forecasters exhibited some skill in predicting when the clear and broken cloud patterns would form in the operations area. They based their predictions on the analysis and simulations of the models run by NOAA's Numeric Meteorological Center. How the atmospheric conditions analyzed by one NOAA/NMC model related to the cloud cover is discussed

Use of microwave satellite data to study variations in rainfall over the Indian Ocean

The University of Wisconsin Space Science and Engineering Center mapped rainfall over the Indian Ocean using a newly developed Scanning Multichannel Microwave Radiometer (SMMR) rain-retrieval algorithm. The short-range objective was to characterize the distribution and variability of Indian Ocean rainfall on seasonal and annual scales. In the long-range, the objective is to clarify differences between land and marine regimes of monsoon rain. Researchers developed a semi-empirical algorithm for retrieving Indian Ocean rainfall. Tools for this development have come from radiative transfer and cloud liquid water models. Where possible, ground truth information from available radars was used in development and testing. SMMR rainfalls were also compared with Indian Ocean gauge rainfalls. Final Indian Ocean maps were produced for months, seasons, and years and interpreted in terms of historical analysis over the sub-continent

An Investigation of Surface Albedo Variations During the Recent Sahel Drought

Applications Technology Satellite (ATS) 3 green sensor data are used to measure surface reflectance variations in the Sahara/Sahel during the recent drought period 1967–74. The magnitude of the seasonal reflectance change is shown to be as much as 80% for years of normal precipitation and less than 50% for drought years. Year-to-year comparisons during both wet and dry seasons reveal the existence of a surface reflectance cycle coincident with the drought intensity. The relationship between the green reflectance and solar albedo is examined and estimated to be about 0.6 times the reflectance change observed by the green channel

A Model for Calculating Desert Aerosol Turbidity Over the Oceans from Geostationary Satellite Data

A technique has been developed to infer the optical thickness of Saharan dust from Synchronous Meteorological Satellite (SMS) brightness measurements at visible wavelengths. The scattering model consists of an air layer, a dust layer and a lower boundary of variable albedo. Single-scatter properties of the dust computed from Mie theory were the basis for calculations by plane-parallel theory of radiative transfer in the dust layer. Radiative interactions between air and dust layers and the lower boundary were calculated with an adding version of the doubling scheme. Optical thickness was determined from satellite brightness measurements through a lookup table produced by the adding program. SMS visible sensors were calibrated from the prelaunch calibration measurements and measurements of sun and space. Error analysis and tests indicate a potential accuracy of ∼0.1 unit of optical thickness. The main limits on accuracy are digitizing resolution of the SMS visible signals, and mistaking clouds for dust in the satellite imagery. This technique of inferring Saharan dust turbidity has been verified and fine-tuned using surface turbidity measurements during GATE and corresponding SMS imagery

Ease of predication does not account for imageability effects in performance: a reply to [Jones, 2002]

In this paper we defend our views against [Jones, 2002] claim that the criticism of the ease of predication hypothesis ( [Jones, 1985]) made by [de Mornay Davies and Funnell, 2000] is “fundamentally flawed.” Jones raises five issues concerning the content of the text, the reliability of effects of ease of predication, the generation of predicates, semantic features, and memory retrieval. We address each of these issues in turn and show that either a critical point raised is not made, or the point is mistaken. More importantly we show that our empirical findings, which are entirely overlooked by Jones, unequivocally support the view that ease of predication does not account for imageability effects in performance

Activity loss is associated with cognitive decline in age-related macular degeneration.

BACKGROUND/METHODS: The objective of this study was to determine whether relinquishing cognitive, physical, and social activities is associated with an increased risk of cognitive decline in patients with age-related macular degeneration (AMD). We conducted a 3-year longitudinal study of 206 nondemented patients with AMD. RESULTS: Twenty-three subjects (14.4%) declined cognitively. Age, sex, education, decline in visual acuity, and number of dropped activities were associated with cognitive decline; each additional dropped activity increased the risk by 58%. Subjects who relinquished three activities were 3.87 times (95% confidence interval, 1.95-7.76) more likely to become demented than subjects who relinquished no activities; those who relinquished five activities were 9.54 times (95% confidence interval, 3.05-30.43) more likely. A multivariate model demonstrated that number of dropped activities was a powerful predictor of cognitive decline after controlling for relevant risk factors, particularly for subjects younger than 80 years of age. CONCLUSIONS: Relinquishing valued activities is associated with an increased risk of cognitive decline in older patients with vision loss caused by AMD. These data suggest the importance of promoting optimal cognitive and physical health in patients with AMD and perhaps other chronic diseases

The Internal-External Security Nexus and EU Police/Rule of Law Missions in the Western Balkans

Common Security and Defence Policy (CSDP) police/rule of law missions in the Western Balkans are increasingly guided by externally imposed normative agendas that respond primarily to EU internal security needs rather than functional imperatives or local realities. In line with these needs, EU police reform efforts tend to prioritise effectiveness and crime fighting over longer- term democratic policing and good governance reforms. In practice this means that police reform initiatives are technocratically oriented, yet value ridden fitting EU security concerns and needs. As a result, the police reform process can be—and often is—disconnected from the political and socio-economic reforms necessary for long-term stability and sustainable peace. Police assistance in Bosnia and Herzegovina has been shaped by a determined albeit questionable focus on organised crime and corruption. The focus of EU police reform in Macedonia on primarily crime-fighting aspects of policing has compromised the functioning of the Macedonian police. Similarly, the politics of (non-)recognition of Kosovo's self-proclaimed independence and the intrusiveness of EULEX Kosovo's executive mandate contravene meeting local challenges