Laserfiche WebLink
<br />This report investigates some of the thermodynamic features thought to be <br />relevant to convective cloud development by examining the variability in the <br />thermodynamic structure of rawinsonde data and concurrent satellite observa- <br />tions of cloud structure. The summary is based on cloud characteristics and <br />thermodynamic conditions diagnosed by a simple one-dimensional, steady-state <br />Lagrangian parcel model; namely, the GPCM (Great Plains Cloud Model), devel- <br />oped by Hirsch (1971). In addition, important thermodynamic features related <br />to cloud-base height, required surface heating, and stability and moisture <br />profiles are analyzed for all soundings. The results are qualified by taking <br />into account (1) the limitations of one-dimensional, steady-state cloud <br />models, and (2) problems related to the natural variability of thermodynamics <br />affecting cloud grow~h. <br /> <br />2. Data <br /> <br />a. Rawinsonde Observations <br /> <br />Rawinsonde soundings were regularly taken at a number of locations throughout <br />the High Plains of the United States as part of HIPLEX during the summer <br />months from 1975 to 1977 (fig. 1). The number di~tribution of soundings by <br />location and year is shown in table 1. All soundings were checked for <br />hydrostatic consistency and accuracy and only those that passed the checks <br />and which reached beyond the 20-kPa level were accepted for model analysis <br />(Matthews and Politte, 1980). <br /> <br />Soundings were made routinely on all days during the field season except <br />when the operation stood down for rest periods and major equipment repairs. <br />These standdownperiods were scheduled during periods of no convective <br />activity (generally 10 percent of each field season). On intensive case <br /> <br />2 <br />