Intra-annual Analysis of the North American Snow Cover–Monsoon Teleconnection: Seasonal Forecasting Utility

Hawkins, Timothy W.; Ellis, Andrew W.; Skindlov, Jon A.; Reigle, Dallas

doi:10.1175/1520-0442(2002)015<1743:iaaotn>2.0.co;2

Cited by 27 publications

(36 citation statements)

References 26 publications

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“…Byrne et al, 1999), and seasonal forecasting (e.g. Hawkins et al, 2002). These questions were addressed by carrying out a principle components (PCs) analysis of annual snow cover series, by correlation analysis of the significant PC series with regional temperature and precipitation and with the leading modes of atmospheric circulation identified above, and by a composite analysis of extreme snow years ensembles.…”

Section: Ncp-mentioning

confidence: 99%

Snow cover variability in Bulgarian mountainous regions, 1931–2000

Brown

Petkova

2007

Intl Journal of Climatology

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Abstract:Principal component (PC) analysis was carried out on annual snow cover series from 15 mountain climate stations in Bulgaria to characterize the spatial and temporal variability in snow cover over the 1931-2000 period. Three distinct snow cover response regions were identified: (1) high elevation sites above 1500 m in the Vitosha and Rila Mountains; (2) low elevation sites below 1000 m in the eastern Rhodope and southern Pirin Mountains and (3) a mid-mountain zone of 1000-1500 m elevation including stations from several mountain ranges. Snow cover exhibited evidence of significant decadal-scale variability over the 1931-2000 period but little evidence of long-term trends linked to climate warming. Over the more recent 1971-2000 period, the mid-mountain zone has increased in importance and shows a significant trend toward a later start to the snow cover season.Composite analysis of high and low snow accumulation winters showed high accumulation years associated with a negative North Atlantic Oscillation (NAO)/East Atlantic (EA)-like pattern that favored increased winter precipitation over the Mediterranean and Balkans and anomalous easterly flow across the Black Sea into Bulgaria. Low snow accumulation years were associated with the positive mode of a Scandinavian (SCA)-like pattern that generated fall warming, a delay to the start of the snow cover season and reduced winter precipitation. Correlation of annual snow cover series with these modes of atmospheric variability revealed few significant correlations but evidence of considerable secular variability in the strength and sign of the relationships. This reflects the complex climate regime of Bulgaria, which is located at the cross-roads of Mediterranean and Continental climate influences and on the periphery of the main nodes of influence of Northern Hemisphere circulation patterns that play important roles in European snow cover variability.

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Section: Ncp-mentioning

confidence: 99%

Snow cover variability in Bulgarian mountainous regions, 1931–2000

Brown

Petkova

2007

Intl Journal of Climatology

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“…Reducing the uncertainty in high latitude snow extent and snow duration estimates during the melt period is essential because high latitude snow cover both forces (for example Gong et al, 2003a,b;Watanabe & Nitta, 1999) and responds (for example Bamzai, 2003;Saito & Cohen, 2003) to atmospheric circulation. A number of studies have reported significant correlations between NH spring and summer snow covered area anomalies and subsequent NH winter circulation (Ellis & Hawkins, 2001;Gong et al, 2003a;Hawkins et al, 2002;Saunders et al, 2003) which appears to be related to large-scale wave activity fluxes and impacts on the polar vortex.…”

Section: Introductionmentioning

confidence: 99%

Assessment of spring snow cover duration variability over northern Canada from satellite datasets

Brown

Derksen

Wang

2007

Remote Sensing of Environment

107

105

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“…In addition, previous studies indicate the summertime daily precipitation over the southwestern United States is influenced by numerous multiscalar processes, including large-scale atmospheric circulation patterns (Adams and Comrie 1997;Comrie and Glenn 1998;Ellis and Hawkins 2001;Hawkins et al 2002), mesoscale convective systems (Nieto-Ferreira et al 1997;Carvalho and Jones 2001), mesoscale to synoptic-scale squall lines (Cohen et al 1995), the Madden-Julian oscillation (MJO; e.g., Higgins et al 2004), and Gulf of California surges (Stensrud et al 1997;Fuller and Stensrud 2000;Douglas and Leal 2003).…”

Section: Introductionmentioning

confidence: 99%

Stochastic Modeling of Daily Summertime Rainfall over the Southwestern United States. Part II: Intraseasonal Variability

Wang

Anderson

Salvucci

2007

Journal of Hydrometeorology

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The intraseasonal variability of summertime precipitation over the southwestern United States is examined using stochastic daily occurrence models combined with empirical daily rainfall distributions to document 1) the seasonal evolution of the frequency and intensity of rainfall events across the summertime monsoon season and 2) the climatological evolution of wet spells, dry spells, and storm events. Study results indicate that the evolution of the North American monsoon system (NAMS) is most apparent in the occurrence of daily rainfall events, which exhibit clear time dependence across the summer season over the southwestern United States and can be principally portrayed by stochastic models. In contrast, the seasonal evolution of NAMS is largely absent in the averaged daily rainfall amount time series. There is also a significant seasonal evolution in the length of dry spells. In the central area of the domain (approximately 39 out of 78 stations) dry-spell lengths tend to increase over the course of the summer season, while on the western fringe (8 out of 78 stations) dry-spell lengths tend to decrease. In contrast, wet spells tend to exhibit constant lengths over the course of the season (44 out of 78 stations). The seasonal trend for storms indicates that the number and duration of storms tend to decrease in September; however, the storm depths tend to be more intense, particularly over the western portion of the domain. Overall, 90% of the area-averaged variance for dry-spell lengths can be explained by the random daily evolution of the stochastic model alone. For wet-spell lengths, the area-averaged variance explained by the stochastic models is 98% and for storm amounts it is 92%. These results suggest that the characteristics of most intraseasonal events over this region (i.e., spell lengths and storm amounts) can be captured by the random evolution of daily rainfall models, even with constant year-to-year statistical parameters, indicating that systematic variations in the background climatic conditions from one year to the next may contribute little to the characteristics of these events.

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Intra-annual Analysis of the North American Snow Cover–Monsoon Teleconnection: Seasonal Forecasting Utility

Cited by 27 publications

References 26 publications

Snow cover variability in Bulgarian mountainous regions, 1931–2000

Snow cover variability in Bulgarian mountainous regions, 1931–2000

Assessment of spring snow cover duration variability over northern Canada from satellite datasets

Stochastic Modeling of Daily Summertime Rainfall over the Southwestern United States. Part II: Intraseasonal Variability

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