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Revealing the Winds under the Rain. Part I: Passive Microwave Rain Retrievals Using a New Observation-Based Parameterization of Subsatellite Rain Variability and Intensity—Algorithm Description
Scatterometer ocean surface winds have been providing very valuable information to researchers and operational
weather forecasters for over 10 years. However, the scatterometer wind retrievals are compromised when
rain is present. Merely flagging all rain-affected areas removes the most dynamic and interesting areas from the
wind analysis. Fortunately, the Advanced Earth Observing Satellite II (ADEOS-II) mission carried a radiometer
[the Advanced Microwave Scanning Radiometer (AMSR)] and a scatterometer, allowing for independent, collocated
retrievals of rain. The authors developed an algorithm that uses AMSR observations to estimate the rain
inside the scatterometer beam. This is the first in a series of papers that describe their approach to providing rain
estimation and correction to scatterometer observations. This paper describes the retrieval algorithm and evaluates
it using simulated data. Part II will present its validation when applied to AMSR observations. This passive
microwave rain retrieval algorithm addresses the issues of nonuniform beam filling and hydrometeor uncertainty
in a novel way by 1) using a large number of soundings to develop the retrieval database, thus accounting for the
geographically varying atmospheric parameters; 2) addressing the spatial inhomogeneity of rain by developing
multiple retrieval databases with different built-in inhomogeneity and rain intensity, along with a ‘‘rain indicator’’
to select the most appropriate database for each observed scene; 3) developing a new cloud-versus-rain partitioning
that allows the use of a variety of drop size distribution assumptions to account for some of the natural
variability diagnosed from the soundings; and 4) retrieving atmospheric and surface parameters just outside the
rainy areas, thus providing information about the environment to help decrease the uncertainty of the rain estimates.Keywords: Precipitation, Satellite observations, Algorithms, Radiative transfer, Microwave observations, Remote sensin
Clinical field study to evaluate the efficacy and safety of the amino-acetonitrile derivative, monepantel, compared with registered anthelmintics against gastrointestinal nematodes of sheep in Australia
Objective: To determine the efficacy of monepantel, a developmental compound from the amino-acetonitrile derivative class of anthelmintics, against field infections of gastrointestinal nematodes in sheep. Procedures: Comparisons of efficacy (using standard faecal worm egg count reduction tests) and safety (on the basis of visual observations) were made in a large-scale field study in Australia, between groups of sheep treated with either an oral solution of monepantel or a registered anthelmintic. The sheep were naturally infected with the major gastrointestinal nematode genera present in Australia. Results: The post-treatment efficacy results for monepantel were: at 7 days (±1 day) efficacy was >98%; at 14 days (±1 day) it was generally close to or >99%; and at 21 days (±1 day) efficacy was consistently >99%. A high proportion of the targeted nematode populations were confirmed as being resistant to one or more of the currently available anthelmintic classes. Conclusions: Monepantel when used under field conditions at a minimum dose rate of 2.5 mg/kg was highly effective against mixed-genus natural field infections of the major gastrointestinal nematode genera including Haemonchus, Teladorsagia (Ostertagia), Trichostrongylus, Nematodirus, Chabertia and Oesophagostomum. This result included efficacy against some populations resistant to the currently available broad-spectrum anthelmintics. Few Cooperia spp. were present to allow confirmation of efficacy against this genus. On no occasion after treatment did any commercial anthelmintic-treated groups have significantly lower faecal egg counts than the monepantel-treated groups. Monepantel was safe for the target animals and human operators when used in a field situation.BC Hosking, TM Griffiths, RG Woodgate, RB Besier, AS Le Feuvre, P Nilon, C Trengove, KJ Vanhoff, BG Kaye-Smith and W Seewal