scholarly journals THE ROLE OF WINTER PRECIPITATION AS A CLIMATIC DRIVER OF THE SPRING PHENOLOGY OF FIVE CALIFORNIA QUERCUS SPECIES (FAGACEAE)

Madroño ◽  
2021 ◽  
Vol 68 (4) ◽  
Author(s):  
Wendy Armstrong-Herniman ◽  
Sarah Greenwood
Keyword(s):  
Winter Precipitation ◽  
Spring Phenology ◽  
Quercus Species

Dendroclimatic response of mountain hemlock (Tsuga mertensiana) in Pacific North America

2001 ◽  
Vol 31 (2) ◽  
pp. 322-332 ◽  
Author(s):  
Ze'ev Gedalof ◽  
Dan J Smith
Keyword(s):  
Large Scale ◽  
Winter Precipitation ◽  
Influential Factor ◽  
Limiting Factor ◽  
Study Region ◽  
Queen Charlotte Islands ◽  
Summer Temperatures ◽  
Cross Correlations ◽  
Tsuga Mertensiana

In this paper we review the ecology and physiology of mountain hemlock (Tsuga mertensiana (Bong.) Carrière) in the context of a dendroclimatological analysis. To better understand the relationship between mountain hemlock growth and climate variability throughout its range we have analyzed chronologies from 10 coastal sites, located along a transect extending from northern California to southern Alaska. The chronologies exhibit significant large-scale cross-correlations, with two distinct growth regions implied: chronologies from the northern Cascades in California, to the Queen Charlotte Islands, British Columbia, are correlated with each other but are distinct from Alaskan chronologies. While intervals of coherent reduced growth along the entire transect occur episodically throughout the record, intervals of coherent enhanced growth are less common. Response function analyses indicate that summer temperature is the most influential factor limiting growth throughout the study region, while winter precipitation is an additional limiting factor south of Alaska. Warm summer temperatures are associated with enhanced growth in the current year but with reduced growth in the following year. This response is believed to be a reflection of the energy required to mature cones initiated in the preceding year. The association with winter precipitation may reflect the role of deep, persistent snowpacks in regulating the duration of the growing season.

Unexpected role of winter precipitation in determining heat requirement for spring vegetation green-up at northern middle and high latitudes

2014 ◽  
Vol 20 (12) ◽  
pp. 3743-3755 ◽  
Author(s):  
Yongshuo H Fu ◽  
Shilong Piao ◽  
Hongfang Zhao ◽  
Su-Jong Jeong ◽  
Xuhui Wang ◽  
...  
Keyword(s):  
Winter Precipitation ◽  
High Latitudes ◽  
Heat Requirement

scholarly journals Uncertainty in El Niño-like warming and California precipitation changes linked by the Interdecadal Pacific Oscillation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lu Dong ◽  
L. Ruby Leung ◽  
Fengfei Song ◽  
Jian Lu
Keyword(s):  
El Niño ◽  
El Nino ◽  
Internal Variability ◽  
Winter Precipitation ◽  
Adaptation Planning ◽  
Interdecadal Pacific Oscillation ◽  
The North ◽  
Westerly Jet ◽  
Precipitation Changes

AbstractMarked uncertainty in California (CA) precipitation projections challenges their use in adaptation planning in the region already experiencing severe water stress. Under global warming, a westerly jet extension in the North Pacific analogous to the El Niño-like teleconnection has been suggested as a key mechanism for CA winter precipitation changes. However, this teleconnection has not been reconciled with the well-known El Niño-like warming response or the controversial role of internal variability in the precipitation uncertainty. Here we find that internal variability contributes > 70% and > 50% of uncertainty in the CA precipitation changes and the El Niño-like warming, respectively, based on analysis of 318 climate simulations from several multi-model and large ensembles. The Interdecadal Pacific Oscillation plays a key role in each contribution and in connecting the two via the westerly jet extension. This unifying understanding of the role of internal variability in CA precipitation provides critical guidance for reducing and communicating uncertainty to inform adaptation planning.

scholarly journals Geo-climatic hazards in the eastern subtropical Andes: distribution, climate drivers and trends

2020 ◽  
Vol 20 (5) ◽  
pp. 1353-1367 ◽  
Author(s):  
Iván Vergara ◽  
Stella M. Moreiras ◽  
Diego Araneo ◽  
René Garreaud
Keyword(s):  
20Th Century ◽  
Meteorological Data ◽  
Winter Precipitation ◽  
Positive Trend ◽  
Study Region ◽  
Climatic Hazards ◽  
Eastern Zone ◽  
Western Zone ◽  
Spatio Temporal

Abstract. Detecting and understanding historical changes in the frequency of geo-climatic hazards (G-CHs) is crucial for the quantification of current hazards and project them into the future. Here we focus in the eastern subtropical Andes (32–33∘ S), using meteorological data and a century-long inventory of 553 G-CHs triggered by rainfall or snowfall. We first analyse their spatio-temporal distributions and the role of climate variability in the year-to-year changes in the number of days per season with G-CHs. Precipitation is positively correlated with the number of G-CHs across the region and year-round; mean temperature is negatively correlated with snowfall-driven hazards in the western (higher) half of the study region during winter and with rainfall-driven hazards in the eastern zone during summer. The trends of the G-CH frequency since the mid-20th century were calculated, paying attention to their non-systematic monitoring. The G-CH series for the different triggers, zones and seasons were generally stationary. Nonetheless, there is a small positive trend in rainfall-driven G-CHs in the eastern zone during summer, congruent with a rainfall increase there. We also found a decrease in snowfall-driven G-CHs in the western zone from the late 1990s onwards, most likely due to a reduction in winter precipitation rather than to an increase in temperature.

Improving the Prediction of Winter Precipitation and Temperature over the Continental United States: Role of the ENSO State in Developing Multimodel Combinations

2010 ◽  
Vol 138 (6) ◽  
pp. 2447-2468 ◽  
Author(s):  
Naresh Devineni ◽  
A. Sankarasubramanian
Keyword(s):  
General Circulation ◽  
General Circulation Models ◽  
Winter Precipitation ◽  
Skill Levels ◽  
Higher Weights ◽  
Atmospheric General Circulation Models ◽  
Multimodel Ensembles ◽  
Precipitation And Temperature

Abstract Recent research into seasonal climate prediction has focused on combining multiple atmospheric general circulation models (GCMs) to develop multimodel ensembles. A new approach to combining multiple GCMs is proposed by analyzing the skill levels of candidate models contingent on the relevant predictor(s) state. To demonstrate this approach, historical simulations of winter (December–February, DJF) precipitation and temperature from seven GCMs were combined by evaluating their skill—represented by mean square error (MSE)—over similar predictor (DJF Niño-3.4) conditions. The MSE estimates are converted into weights for each GCM for developing multimodel tercile probabilities. A total of six multimodel schemes are considered that include combinations based on pooling of ensembles as well as on the long-term skill of the models. To ensure the improved skill exhibited by the multimodel scheme is statistically significant, rigorous hypothesis tests were performed comparing the skill of multimodels with each individual model’s skill. The multimodel combination contingent on Niño-3.4 shows improved skill particularly for regions whose winter precipitation and temperature exhibit significant correlation with Niño-3.4. Analyses of these weights also show that the proposed multimodel combination methodology assigns higher weights for GCMs and lesser weights for climatology during El Niño and La Niña conditions. On the other hand, because of the limited skill of GCMs during neutral Niño-3.4 conditions, the methodology assigns higher weights for climatology resulting in improved skill from the multimodel combinations. Thus, analyzing GCMs’ skill contingent on the relevant predictor state provides an alternate approach for multimodel combinations such that years with limited skill could be replaced with climatology.

The role of ENSO and PDO in variability of winter precipitation over North America from twenty first century CMIP5 projections

2015 ◽  
Vol 46 (9-10) ◽  
pp. 3259-3277 ◽  
Author(s):  
Ramón Fuentes-Franco ◽  
Filippo Giorgi ◽  
Erika Coppola ◽  
Fred Kucharski
Keyword(s):  
North America ◽  
Winter Precipitation ◽  
First Century ◽  
Twenty First Century

scholarly journals Geo-climatic hazards in the eastern subtropical Andes: Distribution, Climate Drivers and Trends

2020 ◽  
Author(s):  
Iván Vergara ◽  
Stella M. Moreiras ◽  
Diego Araneo ◽  
René Garreaud
Keyword(s):  
Meteorological Data ◽  
Winter Precipitation ◽  
Positive Trend ◽  
Future Projection ◽  
Study Region ◽  
Climatic Hazards ◽  
Eastern Zone ◽  
Western Zone ◽  
Spatio Temporal

Abstract. Detection and understanding of historical changes in the frequency of geo-climatic hazards (G-CHs) is crucial for the quantification of current hazard and their future projection. Here we focus in the eastern subtropical Andes (32–33° S), using meteorological data and a century-long inventory on 553 G-CHs triggered by rainfall or snowfall. First we analysed their spatio-temporal distributions and the role of climate variability on the year-to-year changes in the number of days with G-CHs. Precipitation is positively correlated with the number of G-CHs across the region and year-round; mean temperature is negatively correlated with snowfall-driven hazards in the western (higher) half of the study region during winter, and with rainfall-driven hazards in the eastern zone during summer. The trends of the G-CHs frequency since the mid-20th century were calculated taking cautions for their non-systematic monitoring. The G-CHs series for the different triggers, zones and seasons were generally stationary. Nonetheless, there is a small positive trend in rainfall-driven G-CHs in the eastern zone during summer congruent with a rainfall increase there. We also found a decrease in snowfall-driven G-CHs in the western zone since the late 1990's onwards, most likely due to a reduction in winter precipitation rather than an increase in temperature.

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