TY - JOUR
T1 - Meteorological indicators of summer precipitation chemistry in central Pennsylvania
AU - Dayan, Uri
AU - Lamb, Dennis
PY - 2003/3
Y1 - 2003/3
N2 - Daily precipitation chemistry data from nine consecutive summers (1993-2001) at a central Pennsylvania site were analyzed by objective and subjective methods and classified into key synoptic-scale circulation types. Significant differences in acidity and analyte concentrations were found among the seven storm types. The Convective type had the highest mean concentrations for all major ions compared to the Warm-Front (WF) type, which featured the lowest concentrations. The highest sulfate-to-nitrate ratio (2.36), assigned to the Warm-Sector (WS) type, indicates that acidity within air-masses transported to central Pennsylvania from the southwest is primarily in the form of H2SO4. About 20% of the overall acidity in precipitation during summer is neutralized by base cations. Both the Low-to-South and WF types have the lowest magnitudes of neutralization due to a lack of base cations of crustal origin. Both circulation systems are featured by an onshore flow from the Atlantic Ocean. Meteorological indicators for each weather type were developed based on values and geographical locations of anomalies of synoptic-scale variables, expressed as significant departures from their long-term means (as extracted from the Reanalysis NCEP/NCAR Model). The results suggest distinctive patterns for the regional position of the anomalies for the differing circulation systems. The two warm-weather types (High-to-South and Convective and WS) are featured by negative anomalies of sea-level pressure (SLP) and 850hPa geopotential height (GPH) located northwest of the site and positive anomalies of the 850hPa temperature to the east. Both are also associated with deep convection. The Cold-Front and Low-to-East types manifest an opposite symmetrical position of the anomalies, i.e., negative anomalies of SLP and 850hPa GPH to the northeast and negative 850hPa temperature anomalies northwest of the site. Both types are characterized by lower lifted indices, indicating weak atmospheric instability.
AB - Daily precipitation chemistry data from nine consecutive summers (1993-2001) at a central Pennsylvania site were analyzed by objective and subjective methods and classified into key synoptic-scale circulation types. Significant differences in acidity and analyte concentrations were found among the seven storm types. The Convective type had the highest mean concentrations for all major ions compared to the Warm-Front (WF) type, which featured the lowest concentrations. The highest sulfate-to-nitrate ratio (2.36), assigned to the Warm-Sector (WS) type, indicates that acidity within air-masses transported to central Pennsylvania from the southwest is primarily in the form of H2SO4. About 20% of the overall acidity in precipitation during summer is neutralized by base cations. Both the Low-to-South and WF types have the lowest magnitudes of neutralization due to a lack of base cations of crustal origin. Both circulation systems are featured by an onshore flow from the Atlantic Ocean. Meteorological indicators for each weather type were developed based on values and geographical locations of anomalies of synoptic-scale variables, expressed as significant departures from their long-term means (as extracted from the Reanalysis NCEP/NCAR Model). The results suggest distinctive patterns for the regional position of the anomalies for the differing circulation systems. The two warm-weather types (High-to-South and Convective and WS) are featured by negative anomalies of sea-level pressure (SLP) and 850hPa geopotential height (GPH) located northwest of the site and positive anomalies of the 850hPa temperature to the east. Both are also associated with deep convection. The Cold-Front and Low-to-East types manifest an opposite symmetrical position of the anomalies, i.e., negative anomalies of SLP and 850hPa GPH to the northeast and negative 850hPa temperature anomalies northwest of the site. Both types are characterized by lower lifted indices, indicating weak atmospheric instability.
KW - Meteorological indicators
KW - NADP/AIRMoN
KW - Precipitation chemistry
KW - Synoptic circulation
KW - Wet deposition
UR - http://www.scopus.com/inward/record.url?scp=0037332458&partnerID=8YFLogxK
U2 - 10.1016/S1352-2310(02)00992-5
DO - 10.1016/S1352-2310(02)00992-5
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:0037332458
SN - 1352-2310
VL - 37
SP - 1045
EP - 1055
JO - Atmospheric Environment
JF - Atmospheric Environment
IS - 8
ER -