Abstract: Sensitivity experiments with a perpetual January version of a low-resolution general circulation model are conducted to investigate the influence of mountains on blocking in the Northern Hemisphere. Two 1200-day integrations, ...

Abstract: Sensitivity experiments with a perpetual January version of a low-revolution general circulation model (GCM) are conducted to investigate the influence of different, nonzero specifications of orography on low-frequency ...

Abstract: The large-scale environment of small synoptic-scale cyclones that occur in polar air streams over the wintertime North Pacific behind or poleward of major frontal bands is objectively documented by the compositing of ...

Abstract: Sanders and Gyakum's (1980) 24-hour criterion (a central pressure fall that averages at least 1 mb h?1 for 24 h) of a rapidly deepening extratropical surface cyclone is adopted to investigate explosive surface cyclogenesis ...

Abstract: Blocking anticyclones that appear in perpetual January simulations of a spectral general circulation model are examined. Blocks in three geographical regions are studied: the North Pacific, the North Atlantic and western ...

Abstract: A polar air stream cyclogenesis over the wintertime North American Continent is documented. Numerous similarities are found between this land case and oceanic polar lows studied Harrold and Browning (1969), Reed (1979) and ...

Abstract: The systematic error and uncertainty of surface analyses produced by the National Meteorological Center (NMC) over the North Pacific Ocean is estimated. Differences in cyclone position, central pressure, and 12-h deepening ...

Abstract: The net forcing of blocking flows by transient eddies having synoptic time scales is examined within the framework of quasi-geostrophic theory. Temporal filtering is used to distinguish the effects of transients having ...

Abstract: Sensitivity experiments with a perpetual January version of a low-resolution general circulation model are conducted to investigate the influence of Pacific sea surface temperature (SST) anomalies on blocking in the Northern ...

Abstract: The occurrence of explosive cyclogenesis is studied in two 180-day cold-season simulations by the Community Climate Models (CCM1 and CCM2) developed at the National Center for Atmospheric Research. The CCM1 run was realistic ...