scholarly journals Spatial coherence of interannual variability in water properties on the U.S. northeast shelf

1998 ◽  
Vol 103 (C2) ◽  
pp. 3083-3092 ◽  
Author(s):  
David G. Mountain ◽  
Maureen H. Taylor
Keyword(s):  
Interannual Variability ◽  
Spatial Coherence ◽  
Water Properties ◽  
The U.S

Seasonal and interannual variability in13C composition of ecosystem carbon fluxes in the U.S. Southern Great Plains

Tellus B ◽  
2011 ◽  
Vol 63 (2) ◽  
Author(s):  
Margaret S. Torn ◽  
Sebastien C. Biraud ◽  
Christopher J. Still ◽  
William J. Riley ◽  
Joe A. Berry
Keyword(s):  
Interannual Variability ◽  
Great Plains ◽  
Carbon Fluxes ◽  
Southern Great Plains ◽  
Seasonal And Interannual Variability ◽  
Ecosystem Carbon ◽  
Ecosystem Carbon Fluxes ◽  
The U.S

scholarly journals Spatial Coherence of Monsoon Onset over Western and Central Sahel (1950–2000)

2009 ◽  
Vol 22 (5) ◽  
pp. 1313-1324 ◽  
Author(s):  
Romain Marteau ◽  
Vincent Moron ◽  
Nathalie Philippon
Keyword(s):  
Burkina Faso ◽  
Interannual Variability ◽  
Large Scale ◽  
Spatial Coherence ◽  
Daily Rainfall ◽  
Local Scale ◽  
Monsoon Onset ◽  
Onset Date ◽  
Dry Spell

Abstract The spatial coherence of boreal monsoon onset over the western and central Sahel (Senegal, Mali, Burkina Faso) is studied through the analysis of daily rainfall data for 103 stations from 1950 to 2000. Onset date is defined using a local agronomic definition, that is, the first wet day (>1 mm) of 1 or 2 consecutive days receiving at least 20 mm without a 7-day dry spell receiving less than 5 mm in the following 20 days. Changing either the length or the amplitude of the initial wet spell, or both, or the length of the following dry spell modifies the long-term mean of local-scale onset date but has only a weak impact either on its interannual variability or its spatial coherence. Onset date exhibits a seasonal progression from southern Burkina Faso (mid-May) to northwestern Senegal and Saharian edges (early August). Interannual variability of the local-scale onset date does not seem to be strongly spatially coherent. The amount of common or covariant signal across the stations is far weaker than the interstation noise at the interannual time scale. In particular, a systematic spatially consistent advance or delay of the onset is hardly observed across the whole western and central Sahel. In consequence, the seasonal predictability of local-scale onset over the western and central Sahel associated, for example, with large-scale sea surface temperatures, is, at best, weak.

scholarly journals Interannual Sea-Ice Variations and Sea-Ice/Atmosphere Interations in the Southern Ocean, 1973–1975

1982 ◽  
Vol 3 ◽  
pp. 249-254 ◽  
Author(s):  
Claire L. Parkinson ◽  
Donald J. Cavalieri
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Interannual Variability ◽  
Sea Level ◽  
Spatial Dependence ◽  
Spatial Coherence ◽  
Yearly Cycle ◽  
Small Term ◽  
The Mean ◽  
Ice Edge

Examination of satellite-derived 1973–75 sea-ice concentrations for the Southern Ocean and comparison with 1 000 mbar temperatures and sea-level pressures reveal considerable Interannual variability in both the ice and atmospheric fields plus strong suggestions of ice/atmosphere interconnections. The mean position of the ice edge undergoes a strong yearly cycle that lags the cycle of the zonally-averaged temperatures by about one month, but the mean ice edge does not contain small-term fluctuations or interannual variability to the same extent as either the temperature or the pressure. Regionally, the ice varies much more noticeably from year-to-year, with the interannual contrasts showing strong spatial dependence in all months and strong spatial coherence in winter. These are illustrated by selected maps of monthly differences in ice concentrations between 1973 and 1974 and between 1974 and 1975. It is shown that the interannual ice differences can, in many cases, be attributed to the Interannual differences in the positioning and intensity of cyclonic and anticyclonic systems.

scholarly journals Seasonal Predictability and Spatial Coherence of Rainfall Characteristics in the Tropical Setting of Senegal

2006 ◽  
Vol 134 (11) ◽  
pp. 3248-3262 ◽  
Author(s):  
Vincent Moron ◽  
Andrew W. Robertson ◽  
M. Neil Ward
Keyword(s):  
Interannual Variability ◽  
General Circulation ◽  
Degrees Of Freedom ◽  
Regional Scale ◽  
Spatial Coherence ◽  
Daily Rainfall ◽  
Occurrence Frequency ◽  
Seasonal Rainfall ◽  
Mean Intensity ◽  
Rainfall Occurrence

Abstract This study examines space–time characteristics of seasonal rainfall predictability in a tropical region by analyzing observed data and model simulations over Senegal. Predictability is analyzed in terms of the spatial coherence of observed interannual variability at the station scale, and within-ensemble coherence of general circulation model (GCM) simulations with observed sea surface temperatures (SSTs) prescribed. Seasonal mean rainfall anomalies are decomposed in terms of daily rainfall frequency and daily mean intensity. The observed spatial coherence is computed from a 13-station network of daily rainfall during the July–September season 1961–98 in terms of (i) interannual variability of a standardized anomaly index (i.e., the average of the normalized anomalies of each station), (ii) the external variance (i.e., the fraction of common variance among stations), and (iii) the number of spatiotemporal degrees of freedom. Spatial coherence of interannual anomalies across stations is found to be much stronger for seasonal rainfall amount and daily occurrence frequency, compared with daily mean intensity of rainfall. Combinatorial analysis of the station observations suggests that, for occurrence and seasonal amount, the empirical number of spatial degrees of freedom is largely insensitive to the number of stations considered, and is between 3 and 4 for Senegal. For daily mean intensity, by contrast, each station is found to convey almost independent information, and the number of degrees of freedom would be expected to increase for a denser network of stations. The GCM estimates of potential predictability and skill associated with the SST forcing are found to be remarkably consistent with those inferred from the observed spatial coherence: there is a moderate-to-strong skill at reproducing the interannual variations of seasonal amounts and rainfall occurrence, whereas the skill is weak for the mean intensity of rainfall. Over Senegal during July–September, it is concluded that (i) regional-scale seasonal amount and rainfall occurrence frequency are predictable from SSTs, (ii) daily mean intensity of rainfall is spatially incoherent and largely unpredictable at the regional scale, and (iii) point-score estimates of seasonal rainfall predictability and skill are subject to large sampling variability.

scholarly journals Interannual Sea-Ice Variations and Sea-Ice/Atmosphere Interations in the Southern Ocean, 1973–1975

1982 ◽  
Vol 3 ◽  
pp. 249-254 ◽  
Author(s):  
Claire L. Parkinson ◽  
Donald J. Cavalieri
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Interannual Variability ◽  
Sea Level ◽  
Spatial Dependence ◽  
Spatial Coherence ◽  
Yearly Cycle ◽  
Small Term ◽  
The Mean ◽  
Ice Edge

Examination of satellite-derived 1973–75 sea-ice concentrations for the Southern Ocean and comparison with 1 000 mbar temperatures and sea-level pressures reveal considerable Interannual variability in both the ice and atmospheric fields plus strong suggestions of ice/atmosphere interconnections. The mean position of the ice edge undergoes a strong yearly cycle that lags the cycle of the zonally-averaged temperatures by about one month, but the mean ice edge does not contain small-term fluctuations or interannual variability to the same extent as either the temperature or the pressure. Regionally, the ice varies much more noticeably from year-to-year, with the interannual contrasts showing strong spatial dependence in all months and strong spatial coherence in winter. These are illustrated by selected maps of monthly differences in ice concentrations between 1973 and 1974 and between 1974 and 1975. It is shown that the interannual ice differences can, in many cases, be attributed to the Interannual differences in the positioning and intensity of cyclonic and anticyclonic systems.

Interannual Variability of the Cyclonic Activity along the U.S. Pacific Coast: Influences on the Characteristics of Winter Precipitation in the Western United States

2009 ◽  
Vol 22 (21) ◽  
pp. 5732-5747 ◽  
Author(s):  
Boksoon Myoung ◽  
Yi Deng
Keyword(s):  
United States ◽  
Interannual Variability ◽  
Pacific Northwest ◽  
Pacific Coast ◽  
Storm Track ◽  
Winter Precipitation ◽  
Western United States ◽  
Cyclonic Activity ◽  
The Pacific ◽  
The U.S

Abstract This study examines the observed interannual variability of the cyclonic activity along the U.S. Pacific coast and quantifies its impact on the characteristics of both the winter total and extreme precipitation in the western United States. A cyclonic activity function (CAF) was derived from a dataset of objectively identified cyclone tracks in 27 winters (1979/80–2005/06). The leading empirical orthogonal function (EOF1) of the CAF was found to be responsible for the EOF1 of the winter precipitation in the western United States, which is a monopole mode centered over the Pacific Northwest and northern California. On the other hand, the EOF2 of the CAF contributes to the EOF2 of the winter precipitation, which indicates that above-normal precipitation in the Pacific Northwest and its immediate inland regions tends to be accompanied by below-normal precipitation in California and the southwestern United States and vice versa. The first two EOFs of CAF (precipitation) account for about 70% (78%) of the total interannual variance of CAF (precipitation). The second EOF modes of both the CAF and precipitation are significantly linked to the ENSO signal on interannual time scales. A composite analysis further reveals that the leading CAF modes increase (decrease) the winter total precipitation by increasing (decreasing) both the number of rainy days per winter and the extremeness of precipitation. The latter was quantified in terms of the 95th percentile of the daily rain rate and the probability of precipitation being heavy given a rainy day. The implications of the leading CAF modes for the water resources and the occurrence of extreme hydrologic events in the western United States, as well as their dynamical linkages to the Pacific storm track and various atmospheric low-frequency modes (i.e., teleconnection patterns), are also discussed.

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