Monthly Anticyclonicity and Cyclonicity in the Southern Hemisphere: Averages for March and September

On the interpretation and classification of mesoscale cyclones from satellite infrared imagery

“…Here, the 'independent' analysis is the operational product of the Australian Bureau of Meteorology (ABM) Southern Hemisphere sea level pressure charts (see Seaman et al 1993). For those charts, I R cloud imagery from the Japanese Geostationary Meteorological Satellite (GMS), the European Meteosat, and U.S. Geostationary Operational Environmental Satellite (GOES) is rectified to a polar stereographic format, and subjectively interpreted by forecasters to derive the broader-scale atmospheric circulation (Leighton 1994). IR imagery from the NOAA AYHRR supplements the geosynchronous data near Antarctica.…”

“…These images are used to identify mesocyclones and to determine their dominant characteristics for the region south of 50°S, and between approximate longitudes 90°E eastwards to 60°W. This region was selected as part of a larger enquiry into mesocyclones over higher southern latitudes, centred on the Ross Sea sector (Bromwich 1991, Fitch 'and Carleton 1992, Carleton and Fitch 1993, Carrasco and Bromwich 1993, 1994. The IR imagery is used because, unlike the simultaneous visible channel (0'4-1'] Jim), it is uninfluenced by variations in solar illumination.…”

Multidecadal global and regional trends in 1000 mb and 500 mb cyclone frequencies

“…E1 Nifio years are 1965, 1969, 1972, 1976, 1982, 1986, 1991, 1994, 1997La Nifia years are 1964, 1970, 1973, 1975, 1988, 1995 Years are defined to begin in October and continue through the following September. To address this question, mean annual cyclone frequencies were determined for E1 Nifio and La Nifia years as identified by the NCEP climate Prediction Center.…”

“…For example, Colucci (1976) examined the winter cyclone frequencies over the eastern United States and adjacent western Atlantic, Sanders and Gyakum [ 1980] studied cyclogenesis in the northem hemisphere (NH) during 1976 and 1979, Roebber [1984] updated a climatology of explosive cyclones, Zishka et al [ 1980] examined North America and surrounding ocean areas for January and July for 1950-1977, Harman [1987] determined mean monthly North America anticyclone frequencies from 1950-1979, Serreze et al [1993] examined synoptic activity in the Arctic for 1952-1989, Serreze [1995] analyzed patterns of cyclone distribution, deepening rates, and cyclogenesis in the Arctic, Leighton [ 1994] presented monthly anticyclonicity and cyclonicity in the southern hemisphere (SH), and Agee [ 1991] examined the trends in cyclone and anticyclone frequency for the 20th century in the northern hemisphere, and correlated the trends warming and cooling periods. For example, Colucci (1976) examined the winter cyclone frequencies over the eastern United States and adjacent western Atlantic, Sanders and Gyakum [ 1980] studied cyclogenesis in the northem hemisphere (NH) during 1976 and 1979, Roebber [1984] updated a climatology of explosive cyclones, Zishka et al [ 1980] examined North America and surrounding ocean areas for January and July for 1950-1977, Harman [1987] determined mean monthly North America anticyclone frequencies from 1950-1979, Serreze et al [1993] examined synoptic activity in the Arctic for 1952-1989, Serreze [1995] analyzed patterns of cyclone distribution, deepening rates, and cyclogenesis in the Arctic, Leighton [ 1994] presented monthly anticyclonicity and cyclonicity in the southern hemisphere (SH), and Agee [ 1991] examined the trends in cyclone and anticyclone frequency for the 20th century in the northern hemisphere, and correlated the trends warming and cooling periods.…”

“…The frequencies and characteristics of surface cyclones and anticyclones in a variety of regions have been studied by a number of investigators over the last two decades. For example, Colucci (1976) examined the winter cyclone frequencies over the eastern United States and adjacent western Atlantic, Sanders and Gyakum [ 1980] studied cyclogenesis in the northem hemisphere (NH) during 1976 and 1979, Roebber [1984] updated a climatology of explosive cyclones, Zishka et al [ 1980] examined North America and surrounding ocean areas for January and July for 1950-1977, Harman [1987] determined mean monthly North America anticyclone frequencies from 1950-1979, Serreze et al [1993] examined synoptic activity in the Arctic for 1952-1989, Serreze [1995] analyzed patterns of cyclone distribution, deepening rates, and cyclogenesis in the Arctic, Leighton [ 1994] presented monthly anticyclonicity and cyclonicity in the southern hemisphere (SH), and Agee [ 1991] examined the trends in cyclone and anticyclone frequency for the 20th century in the northern hemisphere, and correlated the trends warming and cooling periods.…”