Bias correction of the CCSM4 for improved regional climate modeling of the North American monsoon

2015 ◽  
Vol 46 (9-10) ◽  
pp. 2961-2976 ◽  
Author(s):  
Jonathan D. D. Meyer ◽  
Jiming Jin
Keyword(s):  
North American ◽  
Bias Correction ◽  
Climate Modeling ◽  
Regional Climate ◽  
Regional Climate Modeling ◽  
North American Monsoon ◽  
The North

scholarly journals Toward Assessing NARCCAP Regional Climate Model Credibility for the North American Monsoon: Future Climate Simulations*

2015 ◽  
Vol 28 (17) ◽  
pp. 6707-6728 ◽  
Author(s):  
Melissa S. Bukovsky ◽  
Carlos M. Carrillo ◽  
David J. Gochis ◽  
Dorit M. Hammerling ◽  
Rachel R. McCrary ◽  
...  
Keyword(s):  
Climate Change ◽  
North American ◽  
Southern Oscillation ◽  
Monsoon Season ◽  
Regional Climate ◽  
Global Climate Models ◽  
North American Monsoon ◽  
The North ◽  
Climate Simulations ◽  
Projected Changes

Abstract This study presents climate change results from the North American Regional Climate Change Assessment Program (NARCCAP) suite of dynamically downscaled simulations for the North American monsoon system in the southwestern United States and northwestern Mexico. The focus is on changes in precipitation and the processes driving the projected changes from the regional climate simulations and their driving coupled atmosphere–ocean global climate models. The effect of known biases on the projections is also examined. Overall, there is strong ensemble agreement for a large decrease in precipitation during the monsoon season; however, this agreement and the magnitude of the ensemble-mean change is likely deceiving, as the greatest decreases are produced by the simulations that are the most biased in the baseline/current climate. Furthermore, some of the greatest decreases in precipitation are being driven by changes in processes/phenomena that are less credible (e.g., changes in El Niño–Southern Oscillation, when it is initially not simulated well). In other simulations, the processes driving the precipitation change may be plausible, but other biases (e.g., biases in low-level moisture or precipitation intensity) appear to be affecting the magnitude of the projected changes. The most and least credible simulations are clearly identified, while the other simulations are mixed in their abilities to produce projections of value.

scholarly journals North American Climate in CMIP5 Experiments. Part I: Evaluation of Historical Simulations of Continental and Regional Climatology

2013 ◽  
Vol 26 (23) ◽  
pp. 9209-9245 ◽  
Author(s):  
Justin Sheffield ◽  
Andrew P. Barrett ◽  
Brian Colle ◽  
D. Nelun Fernando ◽  
Rong Fu ◽  
...  
Keyword(s):  
North American ◽  
Regional Climate ◽  
Arctic Sea Ice ◽  
North American Monsoon ◽  
Multimodel Ensemble ◽  
Western Atlantic ◽  
Large Variability ◽  
The North ◽  
North American Climate ◽  
Hydrological Variables

This is the first part of a three-part paper on North American climate in phase 5 of the Coupled Model Intercomparison Project (CMIP5) that evaluates the historical simulations of continental and regional climatology with a focus on a core set of 17 models. The authors evaluate the models for a set of basic surface climate and hydrological variables and their extremes for the continent. This is supplemented by evaluations for selected regional climate processes relevant to North American climate, including cool season western Atlantic cyclones, the North American monsoon, the U.S. Great Plains low-level jet, and Arctic sea ice. In general, the multimodel ensemble mean represents the observed spatial patterns of basic climate and hydrological variables but with large variability across models and regions in the magnitude and sign of errors. No single model stands out as being particularly better or worse across all analyses, although some models consistently outperform the others for certain variables across most regions and seasons and higher-resolution models tend to perform better for regional processes. The CMIP5 multimodel ensemble shows a slight improvement relative to CMIP3 models in representing basic climate variables, in terms of the mean and spread, although performance has decreased for some models. Improvements in CMIP5 model performance are noticeable for some regional climate processes analyzed, such as the timing of the North American monsoon. The results of this paper have implications for the robustness of future projections of climate and its associated impacts, which are examined in the third part of the paper.

scholarly journals Investigating added value of regional climate modeling in North American winter storm track simulations

2017 ◽  
Vol 50 (5-6) ◽  
pp. 1799-1818 ◽  
Author(s):  
E. D. Poan ◽  
P. Gachon ◽  
R. Laprise ◽  
R. Aider ◽  
G. Dueymes
Keyword(s):  
North American ◽  
Climate Modeling ◽  
Regional Climate ◽  
Storm Track ◽  
Regional Climate Modeling ◽  
Added Value ◽  
Winter Storm

scholarly journals Long-Term Changes in the Climatology of Transient Inverted Troughs over the North American Monsoon Region and Their Effects on Precipitation

2016 ◽  
Vol 29 (17) ◽  
pp. 6037-6064 ◽  
Author(s):  
Timothy M. Lahmers ◽  
Christopher L. Castro ◽  
David K. Adams ◽  
Yolande L. Serra ◽  
John J. Brost ◽  
...  
Keyword(s):  
North American ◽  
Climate Model ◽  
Regional Climate ◽  
Track Density ◽  
North American Monsoon ◽  
Northwest Mexico ◽  
The North ◽  
Simulated Precipitation ◽  
Precipitation Estimates ◽  
Resolution Model

Abstract Transient inverted troughs (IVs) are a trigger for severe weather during the North American monsoon (NAM) in the southwest contiguous United States (CONUS) and northwest Mexico. These upper-tropospheric disturbances enhance the synoptic-scale and mesoscale environment for organized convection, increasing the chances for microbursts, straight-line winds, blowing dust, and flash flooding. This work considers changes in the track density climatology of IVs between 1951 and 2010. IVs are tracked as potential vorticity (PV) anomalies on the 250-hPa surface from a regional climate model that dynamically downscales the NCEP–NCAR Reanalysis 1. Late in the NAM season, a significant increase in IV track density over the 60-yr period is observed over Southern California and western Arizona, coupled with a slight decrease over northwest Mexico. Changes in precipitation are evaluated on days when an IV is observed and days without an IV, using high-resolution model-simulated precipitation estimates and CPC gridded precipitation observations. Because of changes in the spatial distribution of IVs during the 1951–2010 analysis period, which are associated with a strengthening of the monsoon ridge, it is suggested that IVs have played a lesser role in the initiation and organization of monsoon convection in the southwest CONUS during recent warm seasons.

Towards Assessing NARCCAP Regional Climate Model Credibility for the North American Monsoon: Current Climate Simulations*

2013 ◽  
Vol 26 (22) ◽  
pp. 8802-8826 ◽  
Author(s):  
Melissa S. Bukovsky ◽  
David J. Gochis ◽  
Linda O. Mearns
Keyword(s):  
North American ◽  
Climate Models ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
North American Monsoon ◽  
The North ◽  
Current Climate ◽  
Depth Analysis

Abstract The authors examine 17 dynamically downscaled simulations produced as part of the North American Regional Climate Change Assessment Program (NARCCAP) for their skill in reproducing the North American monsoon system. The focus is on precipitation and the drivers behind the precipitation biases seen in the simulations of the current climate. Thus, a process-based approach to the question of model fidelity is taken in order to help assess confidence in this suite of simulations. The results show that the regional climate models (RCMs) forced with a reanalysis product and atmosphere-only global climate model (AGCM) time-slice simulations perform reasonably well over the core Mexican and southwest United States regions. Some of the dynamically downscaled simulations do, however, have strong dry biases in Arizona that are related to their inability to develop credible monsoon flow structure over the Gulf of California. When forced with different atmosphere–ocean coupled global climate models (AOGCMs) for the current period, the skill of the RCMs subdivides largely by the skill of the forcing or “parent” AOGCM. How the inherited biases affect the RCM simulations is investigated. While it is clear that the AOGCMs have a large influence on the RCMs, the authors also demonstrate where the regional models add value to the simulations and discuss the differential credibility of the six RCMs (17 total simulations), two AGCM time slices, and four AOGCMs examined herein. It is found that in-depth analysis of parent GCM and RCM scenarios can identify a meaningful subset of models that can produce credible simulations of the North American monsoon precipitation.

scholarly journals Dynamic Downscaling of the North American Monsoon with the NCEP–Scripps Regional Spectral Model from the NCEP CFS Global Model

2011 ◽  
Vol 24 (3) ◽  
pp. 653-673 ◽  
Author(s):  
Steven C. Chan ◽  
Vasubandhu Misra
Keyword(s):  
North American ◽  
Bias Correction ◽  
Seasonal Variability ◽  
Spectral Model ◽  
North American Monsoon ◽  
Southern Mexico ◽  
Low Level ◽  
Regional Spectral Model ◽  
The North ◽  
Low Level Jets

Abstract The June–September (JJAS) 2000–07 NCEP coupled Climate Forecasting System (CFS) global hindcasts are downscaled over the North and South American continents with the NCEP–Scripps Regional Spectral Model (RSM) with anomaly nesting (AN) and without bias correction (control). A diagnosis of the North American monsoon (NAM) in CFS and RSM hindcasts is presented here. RSM reduces errors caused by coarse resolution but is unable to address larger-scale CFS errors even with bias correction. CFS has relatively weak Great Plains and Gulf of California low-level jets. Low-level jets are strengthened from downscaling, especially after AN bias correction. The RSM NAM hydroclimate shares similar flaws with CFS, with problematic diurnal and seasonal variability. Flaws in both diurnal and monthly variability are forced by erroneous convection-forced divergence outside the monsoon core region in eastern and southern Mexico. NCEP reanalysis shows significant seasonal variability errors, and AN shows little improvement in regional-scale flow errors. The results suggest that extreme caution must be taken when the correction is applied relative to reanalyses. Analysis also shows that North American Regional Reanalysis (NARR) NAM seasonal variability has benefited from precipitation data assimilation, but many questions remain concerning NARR’s representation of NAM.

scholarly journals Urban Climates and Climate Change

2020 ◽  
Vol 45 (1) ◽  
pp. 411-444 ◽  
Author(s):  
Valéry Masson ◽  
Aude Lemonsu ◽  
Julia Hidalgo ◽  
James Voogt
Keyword(s):  
Climate Change ◽  
Climate Modeling ◽  
Regional Climate ◽  
Urban Climate ◽  
Regional Climate Modeling ◽  
Climate Impact ◽  
Local Climate ◽  
Urban Climatology ◽  
Recent Developments ◽  
Global Agenda

Cities are particularly vulnerable to extreme weather episodes, which are expected to increase with climate change. Cities also influence their own local climate, for example, through the relative warming known as the urban heat island (UHI) effect. This review discusses urban climate features (even in complex terrain) and processes. We then present state-of-the-art methodologies on the generalization of a common urban neighborhood classification for UHI studies, as well as recent developments in observation systems and crowdsourcing approaches. We discuss new modeling paradigms pertinent to climate impact studies, with a focus on building energetics and urban vegetation. In combination with regional climate modeling, new methods benefit the variety of climate scenarios and models to provide pertinent information at urban scale. Finally, this article presents how recent research in urban climatology contributes to the global agenda on cities and climate change.

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