Obtaining representative meteorological data for watershed-scale hydrological modelling can be difficult and time consuming. Land-based weather stations do not always adequately represent the weather occurring over a watershed, because they can be far from the watershed of interest and can have gaps in their data series, or recent data are not available. This study presents a method for using the Climate Forecast System Reanalysis (CFSR) global meteorological dataset to obtain historical weather data and demonstrates the application to modelling five watersheds representing different hydroclimate regimes. CFSR data are available globally for each hour since 1979 at a 38-km resolution. Results show that utilizing the CFSR precipitation and temperature data to force a watershed model provides stream discharge simulations that are as good as or better than models forced using traditional weather gauging stations, especially when stations are more than 10 km from the watershed. These results further demonstrate that adding CFSR data to the suite of watershed modelling tools provides new opportunities for meeting the challenges of modelling un-gauged watersheds and advancing real-time hydrological modelling. a 'Replace' indicates that values were replaced within an initial range published in the literature, and 'percent' indicates that values were determined by adjusting the base initialization default variables by a certain percentage.

Summary 1.Ecologists have long been interested in the role of climate in shaping species' ranges, and in recent years, this relationship has taken on greater significance because of the need for accurate predictions of the effects of climate change on wildlife populations. Bioclimatic relationships, however, are potentially complicated by various environmental factors operating at multiple spatial and temporal scales. Here, we test the hypothesis that climatic constraints on bird distributions are modified by species-specific responses to weather, urbanization and use of supplemental food. 2. Our analyses focused on 18 bird species with data from over 3000 sites across the north-eastern United States and adjacent Canadian provinces. We use hierarchal occupancy modelling to quantify the effects of short-term weather variation and surrounding urbanization on food stress and probabilities of detection, and how these fine-scale changes modify the role that climate has on the distributions of wintering bird populations at regional scales. 3. Examining site occupancy and supplemental food use across the study region, we found that average minimum temperature was an important factor limiting bird distributions, supporting the hypothesis that the occupancy of wintering birds is limited by climatic constraints. We found that 15 of 18 species (83%) were more energetically stressed (had a higher likelihood of visiting a feeder station) as minimum temperature declined from the seasonal average. Because we found these patterns in populations that regularly visit supplemental food sites and were likely not food-limited, we suggest that resource availability is less important than climate in constraining wintering bird distributions. Across a winter season, local within-winter extinction probabilities were lower and colonization probabilities higher at warmer sites supporting the role of climate-mediated range shifts. Importantly, however, these relationships were modified by the degree of urbanization and species' abilities to persist in human-modified landscapes. 4. Our results suggest that urbanization and behavioural adaptation can modify the role of climate on bird ranges and should be included in future analyses of range shifts because of climate change.

A climatology of East Coast winter storms (ECWS) was developed using an automated procedure. This routine was used along with the NCEP-NCAR reanalysis dataset (1948, 1951-97) to identify storms over the October-April winter season. An array of statistical analyses was used to empirically analyze the interannual variability of these cyclones. To be classified as an ECWS, an area of low pressure was required to have a closed circulation, be located along the east coast of the United States (within the quadrilateral bounded at 45ЊN by 65Њ and 70ЊW and at 30ЊN by 75Њ and 85ЊW), show general movement from the south-southwest to the north-northeast, and contain winds greater than 10.3 m s Ϫ1 (20 kt) for at least one time period (6 h). Storms meeting the above criteria were also required to have a closed circulation and be located within the quadrilateral during one additional 6-h period (not necessarily consecutive with the first). On average, 12 ECWS occurred per season with a maximum in January. Significant trends in storm frequency over the 46-yr period beginning in 1951 are not evident. However, a marginally significant (␣ ϭ 0.10) increase in average storm minimum pressure is noted. Spectral analysis of the ECWS time series shows significant cycles with periods of 2.3, 2.8, 3.4, 4.8, and 10.2 yr, which are in agreement with documented periodicities in joint Atlantic SST and sea level pressure data. Average monthly ECWS frequency anomalies are significantly higher during El Niño months when compared to neutral months over the October-April storm season. ECWS show little or no change in frequency anomalies during La Niña months.