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First ISCCP Regional Experiment (FIRE) Atlantic Stratocumulus Transition Experiment (ASTEX) ECMWF Cloud Data

A special set of analysis products for the Atlantic Stratocumulus Transition Experiment (ASTEX) region during June 1-28, 1992 was prepared by Ernst Klinker and Tony Hollingsworth of the European Centre for Medium-range Forecasting (ECMWF), and reformatted by Chris Bretherton of Univ. of Washington. These analyses, or more correctly initializations and very short range forecasts using the ECMWF T213L30 operational model, incorporate routine observations from the global network and special soundings from ASTEX that were sent to ECMWFduring ASTEX via the GTS telecommunication system. About 650 special soundings were incorporated, including nearly all soundings from SantaMaria, Porto Santo, and the French ship Le Suroit, most of the soundings taken on the Valdivia and Malcolm Baldridge, and almost noneof the soundings from the Oceanus. Surface reports from the research ships were also incorporated into the analyses after the first week of the experiment. Aircraft soundings were not included in the analyses. ECMWF has requested that anyone making use of this data set acknowledge them, and that those investigators publishing research that makes more than casual use of this data set contact Ernst Klinker or Tony Hollingsworth.The data have been decoded by Chris Bretherton into ASCII files, one for each horizontal field at a given level and base time. All data have the same horizontal resolution of 1.25 degrees in latitude and longitude and correspond to base (initialization) times of 00, 06, 12, or 18Z. Different fields have different lat/lon ranges and sets of available vertical levels, as tabulated below. Also, some fields are instantaneous (I) while others are accumulated (A) over the first 6 hours of a forecast initialized at the base time. This is tabulated in the 'time range' column below. Instantaneous fields are bestcompared with data at the base time, while accumulated fields are best compared with data three hours after the base time.Data Set Name ECMWF ECMWF Time Field Units field ID# range abbrev.----------- ------ ----- ----- ----- -----CLOUDS CLW 212 I Cloud liquid water kg/kg CF 213 I Cloud fraction 0-1(lat/lon range: 35W to 05W, 20N to 45N)(levels: 1010,1000,975,950,925,900,875,850,825,800,775,750,700,650,600,550,500,400,300,200,100 HPa)The ECMWF field abbreviation, ID#, field description and units aretaken directly from ECMWF Code Table 2, in case you ever need toconsult with ECMWF about this data set.

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