61 research outputs found
A wind tunnel investigation of the shape of uncharged raindrops in the presence of an external, electric field
Results of a wind tunnel experiment in which electrically uncharged water drops of 500 to 3000 microns equivalent radius are freely suspended in the vertical air stream of the UCLA cloud tunnel are presented. During this suspension the drops were exposed to external vertical electric fields of 500 to 8,000 volts/cm. The change in drop shape with drop size and electric field strength was noted and is discussed in the light of theoretical work cited in the literature which unfortunately does not take into account the effects of air flow past the drop. The wind tunnel study is documented by stills from a 16 mm film record that demonstrates the shape of water drops in response to both hydrodynamic and electric forces
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Use of Cloud Observations and Mesoscale Meteorology Models to Evaluate and Improve Cloud Parameterizations
This research program utilizes satellite and surface-derived cloud observations together with standard meteorological measurements to evaluate and improve our ability to accurately diagnose cloud coverage. Results are to be used to compliment existing or future parameterizations of cloud effects in general circulation models, since nearly all cloud parameterizations must specify a fractional area of cloud coverage when calculating radiative or dynamic cloud effects, and current parameterizations rely on rather crude cloud cover estimates. We have compiled and reviewed a list of formulations used by various climate research groups to specify cloud cover. We find considerable variability between formulations used by various climate and meteorology models, and under some conditions, one formulation will produce a zero cloud amount, while an alternate formulation calculates 95% cloud cover under the same environmental conditions. All formulations hypothesize that cloud cover is predominantly determined by the average relative humidity, although some formulations allow local temperature lapse rates and vertical velocities to influence cloud amount
Ahmed , The Logo of the Elephant Interest Group: Encounters in Marsabit and Notes on His Model and Skeleton
Ahmed , the logo of the Elephant Interest Group, was a male African elephant (Loxodonta africana) that was born about 1919, possibly in the vicinity of Marsabit National Reserve, Kenya, East Africa. The name Ahmed is of Arabic origin (pronounced Ah-med ), and it means praised. At the age of 55 Ahmed was about 3 m (10 ft) tall at the shoulder and weighed approximately 5 metric tons (about 11,000 lbs.). He had huge tusks for his size, measuring about 3 m (10 ft) each and averaging about 70 kg (150 lbs) each. Ahmed\u27s 300 pounds of ivory attracted hunters and, as a result, raised major concern for his safety among scientists and the general public. A total of 5,000 letters and cards was delivered to the East African Wildlife Society and resulted in a Presidential Decree issued by the late President Mzee Jomo Kenyatta to protect Ahmed. In addition, a team of human soldiers was assigned to watch his whereabouts around the clock. On January 17, 1974 Ahmed died, probably of natural causes, and his carcass was found almost two days later near Lake Paradise, in the Reserve. The skin was already in an advanced stage of decomposition. Ahmed was dissected on the spot by a team from the Zimmermann (1973) Limited Taxidermist, headed by Wolfgang Schenk, and the skeleton was transported to Nairobi, the capital, where it was prepared and mounted by J.C. Hillman. A fiberglas replica of the skin was made by Zimmermann\u27s team. The entire operation lasted two years and cost Kenyan Shillings 143,086 (about US $14,500). Both the skeleton and the replica are now on display at the National Museum of Kenya (NMK) in Nairobi. Ahmed is Kenya\u27s most celebrated elephant; he was and still is regarded as a national monument and remains the symbol of conservation. The NMK and the Kenyan Government should be commended for their tremendous efforts in preserving the remains of Ahmed
A comparison of scavenging and deposition processes in global models: results from the WCRP Cambridge Workshop of 1995
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75543/1/j.1600-0889.2000.00980.x.pd
A comparison of scavenging and deposition processes in global models: results from the WCRP Cambridge Workshop of 1995
Simultaneous measurement of nitrous acid, nitric acid, and nitrogen dioxide by means of a novel multipollutant diffusive sampler in libraries and archives
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Use of Cloud Observations and Mesoscale Meteorology Models to Evaluate and Improve Cloud Parameterizations. Final Technical Progress Report, December 1, 1991--September 30, 1996
The main goal of this research effort is to improve methods for calculating cloud cover within climate models. Cloud cover observations are being used with standard meteorological observations to improve the ability to diagnose cloud cover in climate models. Until now, cloud cover and heights have been diagnosed from the US Air force RTNEPH and 3DNEPH archive, although recent CART measurements are also being analyzed. Improved cloud cover formulations have been compared with existing climate model algorithms. Recently, the authors are also refining and validating an innovative Single Column Model (SCM) cumulus parameterization for calculating heating and moistening tendencies, and precipitation rates attributable to subgrid-scale convection not resolved by climate models. This SCM will be tested and evaluated using tropical convective measurements (GATE) and the author will also use incoming measurements from the Oklahoma ARM site. Further development and testing of this SCM could improve the ability to predict convective effects in climate models. The author will quantify the influence of convection on cloud cover using convective measures derived from this SCM. The output of this research will be a family of validated algorithms for assessing cloud cover under a variety of stable, unstable, continental or oceanic conditions, and an improved cumulus parameterization scheme
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