Aridity on the Canadian Plains

2004 ◽  
Vol 56 (2-3) ◽  
pp. 247-259 ◽  
Author(s):  
David J. Sauchyn ◽  
Elaine M. Barrow ◽  
Ron F. Hopkinson ◽  
Peter R. Leavitt
Keyword(s):  
General Circulation ◽  
Historical Context ◽  
Circulation Model ◽  
Climatic Conditions ◽  
Normal Period ◽  
Future Global Warming ◽  
Major Region ◽  
Regional Baseline ◽  
Lake Salinity ◽  
Past Conditions

Abstract The Prairie Ecozone is the only major region of Canada where drought is a landscape hazard; aridity is linked to soil erosion. Management of prairie ecosystems and soil landscapes therefore requires an understanding of past and future trends and variability in regional aridity. We used instrumental and paleoclimatic records to define a regional baseline for prairie aridity, to evaluate the utility of modern climate normals (i.e. 1961-1990) as a benchmark for future climatic change, and to provide a historical context for a range of General Circulation Model (GCM) forecasts of regional aridity. A warm-dry scenario derived from the Canadian GCM projects a significant increase in the area of subhumid and semiarid climate. Tree rings and diatom-inferred lake salinity record prolonged arid events and show that the climate normal period of 1961-1990 may have been the most benign climate of the past 750 years. The climate of the 20th century was anomalous in terms of the absence of sustained drought. Because both lake and tree-ring analyses recorded an abrupt amelioration of climatic conditions near the start of the instrumental record, we suggest that the immediate impacts of future global warming may be to return the prairies to past conditions in which persistent aridity was recorded for intervals of decades or longer.

scholarly journals Do Downscaled General Circulation Models Reliably Simulate Historical Climatic Conditions?

2018 ◽  
Vol 22 (10) ◽  
pp. 1-22 ◽  
Author(s):  
Andrew R. Bock ◽  
Lauren E. Hay ◽  
Gregory J. McCabe ◽  
Steven L. Markstrom ◽  
R. Dwight Atkinson
Keyword(s):  
General Circulation ◽  
Statistical Tests ◽  
Circulation Model ◽  
General Circulation Models ◽  
Climatic Conditions ◽  
Low Flow ◽  
Balance Model ◽  
Monthly Precipitation ◽  
Significance Level ◽  
Ks Test

Abstract The accuracy of statistically downscaled (SD) general circulation model (GCM) simulations of monthly surface climate for historical conditions (1950–2005) was assessed for the conterminous United States (CONUS). The SD monthly precipitation (PPT) and temperature (TAVE) from 95 GCMs from phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5) were used as inputs to a monthly water balance model (MWBM). Distributions of MWBM input (PPT and TAVE) and output [runoff (RUN)] variables derived from gridded station data (GSD) and historical SD climate were compared using the Kolmogorov–Smirnov (KS) test For all three variables considered, the KS test results showed that variables simulated using CMIP5 generally are more reliable than those derived from CMIP3, likely due to improvements in PPT simulations. At most locations across the CONUS, the largest differences between GSD and SD PPT and RUN occurred in the lowest part of the distributions (i.e., low-flow RUN and low-magnitude PPT). Results indicate that for the majority of the CONUS, there are downscaled GCMs that can reliably simulate historical climatic conditions. But, in some geographic locations, none of the SD GCMs replicated historical conditions for two of the three variables (PPT and RUN) based on the KS test, with a significance level of 0.05. In these locations, improved GCM simulations of PPT are needed to more reliably estimate components of the hydrologic cycle. Simple metrics and statistical tests, such as those described here, can provide an initial set of criteria to help simplify GCM selection.

scholarly journals Effects of environmental stressors on daily governance

2018 ◽  
Vol 115 (35) ◽  
pp. 8710-8715 ◽  
Author(s):  
Nick Obradovich ◽  
Dustin Tingley ◽  
Iyad Rahwan
Keyword(s):  
Food Safety ◽  
General Circulation ◽  
Circulation Model ◽  
Climatic Conditions ◽  
Crash Risk ◽  
Regulatory Oversight ◽  
Fatal Crash ◽  
Future Warming ◽  
Vehicular Crashes ◽  
Government Workers

Human workers ensure the functioning of governments around the world. The efficacy of human workers, in turn, is linked to the climatic conditions they face. Here we show that the same weather that amplifies human health hazards also reduces street-level government workers’ oversight of these hazards. To do so, we employ US data from over 70 million regulatory police stops between 2000 and 2017, from over 500,000 fatal vehicular crashes between 2001 and 2015, and from nearly 13 million food safety violations across over 4 million inspections between 2012 and 2016. We find that cold and hot temperatures increase fatal crash risk and incidence of food safety violations while also decreasing police stops and food safety inspections. Added precipitation increases fatal crash risk while also decreasing police stops. We examine downscaled general circulation model output to highlight the possible day-to-day governance impacts of climate change by 2050 and 2099. Future warming may augment regulatory oversight during cooler seasons. During hotter seasons, however, warming may diminish regulatory oversight while simultaneously amplifying the hazards government workers are tasked with overseeing.

scholarly journals Baseline Conditions and Projected Future Hydro-Climatic Change in National Parks in the Conterminous United States

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1704
Author(s):  
William Battaglin ◽  
Lauren Hay ◽  
David Lawrence ◽  
Greg McCabe ◽  
Parker Norton
Keyword(s):  
United States ◽  
Climatic Change ◽  
National Park ◽  
General Circulation ◽  
Circulation Model ◽  
The United States ◽  
Climatic Conditions ◽  
Balance Model ◽  
Climate Simulations ◽  
Baseline Conditions

The National Park Service (NPS) manages hundreds of parks in the United States, and many contain important aquatic ecosystems and/or threatened and endangered aquatic species vulnerable to hydro-climatic change. More effective management of park resources under future hydro-climatic uncertainty requires information on both baseline conditions and the range of projected future conditions. A monthly water balance model was used to assess baseline (1981–1999) conditions and a range of projected future hydro-climatic conditions in 374 NPS parks. General circulation model outputs representing 214 future climate simulations were used to drive the model. Projected future changes in air temperature (T), precipitation (p), and runoff (R) are expressed as departures from historical baselines. Climate simulations indicate increasing T by 2030 for all parks with 50th percentile simulations projecting increases of 1.67 °C or more in 50% of parks. Departures in 2030 p indicate a mix of mostly increases and some decreases, with 50th percentile simulations projecting increases in p in more than 70% of parks. Departures in R for 2030 are mostly decreases, with the 50th percentile simulations projecting decreases in R in more than 50% of parks in all seasons except winter. Hence, in many NPS parks, R is projected to decrease even when p is projected to increase because of increasing T in all parks. Projected changes in future hydro-climatic conditions can also be assessed for individual parks, and Rocky Mountain National Park and Congaree National Park are used as examples.

scholarly journals Spatial climate models for Canada’s forestry community

2013 ◽  
Vol 89 (05) ◽  
pp. 659-663 ◽  
Author(s):  
Daniel McKenney ◽  
John Pedlar ◽  
Michael Hutchinson ◽  
Pia Papadopol ◽  
Kevin Lawrence ◽  
...  
Keyword(s):  
General Circulation ◽  
Climate Models ◽  
Circulation Model ◽  
Smoothing Splines ◽  
The United States ◽  
Senior Author ◽  
Forest Community ◽  
Climate Projections ◽  
Normal Period ◽  
Wide Range

We summarize ongoing efforts at the Canadian Forest Service to produce spatial climate models for Canada and the United States. Our models, which encompass a wide range of variables and spatiotemporal extents, typically employ thin plate smoothing splines to interpolate and extrapolate climate station values as a function of latitude, longitude and elevation. The resulting surfaces can be resolved as grids (i.e., maps) or as point estimates at locations of interest. Recent efforts, detailed here include: updated models for the most recent 30-year normal period (i.e., 1981–2010), moisture balance models, future climate projections using the latest round of general circulation model (GCM) outputs and emissions scenarios, lake ice freeze/thaw models, and growing season models. These models are available to the Canadian forest community and beyond via the internet ( http://cfs.nrcan.gc.ca/projects/3 ) or by contacting the senior author.

scholarly journals Estimating the Local Time of Emergence of Climatic Variables Using an Unbiased Mapping of GCMs: An Application in Semiarid and Mediterranean Chile

2019 ◽  
Vol 20 (8) ◽  
pp. 1635-1647 ◽  
Author(s):  
Cristián Chadwick ◽  
Jorge Gironás ◽  
Sebastián Vicuña ◽  
Francisco Meza
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Statistical Power ◽  
Signal To Noise Ratio ◽  
Circulation Model ◽  
Climatic Conditions ◽  
Climate Change Signal ◽  
Signal To Noise ◽  
Adaptation Measures ◽  
Precipitation And Temperature

Abstract The time at which climate change signal can be clearly distinguished from noise is known as time of emergence (ToE) and is typically detected by a general circulation model (GCM) signal-to-noise ratio exceeding a certain threshold. ToE is commonly estimated at large scales from GCMs, although management decisions and adaptation strategies are implemented locally. This paper proposes a methodology to estimate ToE for both precipitation and temperature at local scales (i.e., river basin). The methodology considers local climatic conditions and unbiased GCM projections to estimate ToE by using the statistical power to find when the climate significantly differs from the historical one. The method suggests that ToE for temperature already occurred in three Chilean basins (Limarí, Maipo, and Maule). However, in terms of precipitation, an earlier ToE is clearly identified for the Maule basin, indicating that risk assessment and adaptation measures should be implemented first in this basin.

scholarly journals Modelling the Antarctic ice-sheet changes through time

1994 ◽  
Vol 20 ◽  
pp. 291-297 ◽  
Author(s):  
W.F. Budd ◽  
D. Jenssen ◽  
B. Coutts
Keyword(s):  
Sea Level ◽  
General Circulation ◽  
Ice Sheet ◽  
Circulation Model ◽  
Glacial Cycle ◽  
Climatic Forcing ◽  
Antarctic Ice Sheet ◽  
Ice Shelves ◽  
Future Global Warming ◽  
The Antarctic

A new assessment is made of the possible range of responses of the Antarctic ice sheet to future global warming by performing a series of sensitivity tests to prescribed climatic forcing with an ice-sheet model. The model includes thermodynamics; it is three-dimensional, with 20 km horizontal grid spacing and 30 points in the vertical, and it treats the ice shelves explicitly. To obtain an appropriate initial present state for the ice sheet, it has been necessary to perform a series of simulations through the last glacial cycle with prescribed forcing including accumulation, sea level are less importantly climatic temperature. For the future climatic forcing, General Circulation Model simulations have been used with particular concern for the changes in the sea-ice cover and ocean warming. Effects of progressive changes have been examined with increases of basal-melt rates up to 10 m a1, surface annual mean temperatures by up to 7°C and surface-accumulation rates to double the present values. Without additional accumulation, the increased basal melt of 10 m a-1would greatly reduce the ice shelves and contribute to sea-level rise of 0.3 m in 100 years and over 0.6 m by 500 years. The additional accumulation counteracts this to dive about zero change by 100 years and -1.2 m by 500 years.

scholarly journals Modelling the Antarctic ice-sheet changes through time

1994 ◽  
Vol 20 ◽  
pp. 291-297 ◽  
Author(s):  
W.F. Budd ◽  
D. Jenssen ◽  
B. Coutts
Keyword(s):  
Sea Level ◽  
General Circulation ◽  
Ice Sheet ◽  
Circulation Model ◽  
Glacial Cycle ◽  
Climatic Forcing ◽  
Antarctic Ice Sheet ◽  
Ice Shelves ◽  
Future Global Warming ◽  
The Antarctic

A new assessment is made of the possible range of responses of the Antarctic ice sheet to future global warming by performing a series of sensitivity tests to prescribed climatic forcing with an ice-sheet model. The model includes thermodynamics; it is three-dimensional, with 20 km horizontal grid spacing and 30 points in the vertical, and it treats the ice shelves explicitly. To obtain an appropriate initial present state for the ice sheet, it has been necessary to perform a series of simulations through the last glacial cycle with prescribed forcing including accumulation, sea level are less importantly climatic temperature. For the future climatic forcing, General Circulation Model simulations have been used with particular concern for the changes in the sea-ice cover and ocean warming. Effects of progressive changes have been examined with increases of basal-melt rates up to 10 m a1, surface annual mean temperatures by up to 7°C and surface-accumulation rates to double the present values. Without additional accumulation, the increased basal melt of 10 m a-1 would greatly reduce the ice shelves and contribute to sea-level rise of 0.3 m in 100 years and over 0.6 m by 500 years. The additional accumulation counteracts this to dive about zero change by 100 years and -1.2 m by 500 years.

Nonlinear responses of white spruce growth to climate variability in interior Alaska

2013 ◽  
Vol 43 (4) ◽  
pp. 331-343 ◽  
Author(s):  
Andrea H. Lloyd ◽  
Paul A. Duffy ◽  
Daniel H. Mann
Keyword(s):  
Picea Glauca ◽  
Boreal Forests ◽  
General Circulation ◽  
Circulation Model ◽  
White Spruce ◽  
Climatic Conditions ◽  
Boosted Regression Trees ◽  
Temperature And Precipitation ◽  
Interior Alaska ◽  
And Function

Ongoing warming at high latitudes is expected to lead to large changes in the structure and function of boreal forests. Our objective in this research is to determine the climatic controls over the growth of white spruce (Picea glauca (Moench) Voss) at the warmest driest margins of its range in interior Alaska. We then use those relationships to determine the climate variables most likely to limit future growth. We collected tree cores from white spruce trees growing on steep, south-facing river bluffs at five sites in interior Alaska, and analyzed the relationship between ring widths and climate using boosted regression trees. Precipitation and temperature of the previous growing season are important controls over growth at most sites: trees grow best in the coolest, wettest years. We identify clear thresholds in growth response to a number of variables, including both temperature and precipitation variables. General circulation model (GCM) projections of future climate in this region suggest that optimum climatic conditions for white spruce growth will become increasingly rare in the future. This is likely to cause short-term declines in productivity and, over the longer term, probably lead to a contraction of white spruce to the cooler, moister parts of its range in Alaska.

The Impact of the Delta Change Approach on the Severity of Ice-jam Flooding Under Future Climate Scenarios

2021 ◽  
Author(s):  
Apurba Das ◽  
Prabin Rokaya ◽  
Karl-Erich Lindenschmidt
Keyword(s):  
General Circulation ◽  
Climate Model ◽  
Circulation Model ◽  
Climatic Conditions ◽  
Future Climate ◽  
Climate Scenarios ◽  
Frequency Distributions ◽  
Ice Jam ◽  
Delta Change ◽  
The Impact

Abstract Projection of the impact of future climate on ice-jam flood intensity is an essential component of a flood mitigation strategy for many northern communities. General Circulation Model (GCM) outputs are used to derive hydrological conditions under future climate scenarios. Although GCMs are often downscaled to a point of interest, there can still be significant differences between modelled climate scenarios and historically observed climate scenarios. Therefore, the model-indicated changes between baseline and future values of climatic scenarios are applied to observed baseline values to estimate projected future values. This can be carried out by using the delta change method which is an approach for adjusting GCM output. This study evaluates the impact of the delta change method on the frequency and severity of ice-jam flooding under a future climate scenario. The Athabasca River at Fort McMurray is presented as the test site. Streamflow conditions were derived from a physically-based hydrological model, Modélisation Environnementale communautaire-Surface Hydrology (MESH), by forcing the Canadian Regional Climate Model (CRCM) driven by the Third Generation Coupled Climate Model (CGCM3) for both baseline (1971–2000) and future (2041–2070) periods. Streamflow under future climatic conditions was developed based on the delta change method for both absolute and relative changes. The adjusting streamflow was then used in a fully dynamic river ice hydraulic model, RIVICE, to project future ice-jam scenarios using a stochastic modelling framework. Finally, the impact of the delta changes on the frequency and severity of simulated ice-jam flooding was assessed by producing ice-jam stage-frequency distributions (SFDs) under future climatic conditions. The results indicate that there is a notable difference in the projected frequency and severity of ice-jam flooding between absolute and relative change approaches.

scholarly journals Modeling precipitation <i>δ</i><sup>18</sup>O variability in East Asia since the Last Glacial Maximum: temperature and amount effects across different timescales

2016 ◽  
Vol 12 (11) ◽  
pp. 2077-2085 ◽  
Author(s):  
Xinyu Wen ◽  
Zhengyu Liu ◽  
Zhongxiao Chen ◽  
Esther Brady ◽  
David Noone ◽  
...  
Keyword(s):  
East Asia ◽  
Temperature Effect ◽  
General Circulation ◽  
Circulation Model ◽  
Northern China ◽  
Climatic Conditions ◽  
Central China ◽  
Maximum Temperature ◽  
Past Climate ◽  
Amount Effect

Abstract. Water isotopes in precipitation have played a key role in the reconstruction of past climate on millennial timescales and longer. However, for midlatitude regions like East Asia with complex terrain, the reliability behind the basic assumptions of the temperature effect and amount effect is based on modern observational data and still remains unclear for past climate. In the present work, we reexamine the two basic effects on seasonal, interannual, and millennial timescales in a set of time slice experiments for the period 22–0 ka using an isotope-enabled atmospheric general circulation model (AGCM). Our study confirms the robustness of the temperature and amount effects on the seasonal cycle over China in the present climatic conditions, with the temperature effect dominating in northern China and the amount effect dominating in the far south of China but no distinct effect in the transition region of central China. However, our analysis shows that neither temperature nor amount effect is significantly dominant over China on millennial and interannual timescales, which is a challenge to those classic assumptions in past climate reconstruction. Our work helps shed light on the interpretation of the proxy record of δ18O from a modeling point of view.

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