The Canadian Regional Climate Model (CRCM) can be used in a simulation mode where it is driven by... more The Canadian Regional Climate Model (CRCM) can be used in a simulation mode where it is driven by objective analyses. In such mode, the model can be validated using various observational datasets. We present an investigation of the CRCM's surface hydrology from a three-year simulation conducted over the Quebec/Labrador territory. In the experiment, the CRCM was run at a 30 km horizontal grid-point spacing on a 100X100 point domain and driven by NCEP (National Center for Environmental Protection) atmospheric objective analyses for the period from June 1992 to May 1995. The CRCM's regional hydrologic budget over a series of catchment basins is investigated and validated through comparison with observations of precipitation, screen temperature, snow cover and runoff data. The model's output is also compared to evaporation data. Spatial analysis of the CRCM's annual runoff shows that the model is in good agreement with basin observations although its precipitation and surface evaporation during summer months are generally too important. On the seasonal scale, the CRCM captures the main features of the annual cycle, and in particular the snow cover accumulation, which is a major element of the hydrologic cycle with its spring melt reaching up to 50% of the annual runoff. Furthermore, investigation of the CRCM's daily precipitation characteristics and comparison with observations provides a more detailed picture of the model's precipitation behavior. Finally, results presented from sensitivity tests in regards to the model's resolution and its domain location help define the set-up for the next CRCM experiment.
This paper discusses the surface hydrology of a two-year simulation conducted over the Québec/Lab... more This paper discusses the surface hydrology of a two-year simulation conducted over the Québec/Labrador territory with the Canadian Regional Climate Model (CRCM). The CRCM was driven by NCEP (National Center for Environmental Protection) atmospheric objective analyses and was run at a 30 km horizontal grid-point spacing. Model results are compared with available observations for the period from June 1992 to
The release of new data constituting the Coupled Model Intercomparison Project—Phase 5 (CMIP5) da... more The release of new data constituting the Coupled Model Intercomparison Project—Phase 5 (CMIP5) database is an important event in both climate science and climate services issues. Although users’ eagerness for a fast transition from CMIP3 to CMIP5 is expected, this change implies some challenges for climate information providers. The main reason is that the two sets of experiments were performed in different ways regarding radiative forcing and hence continuity between both datasets is partially lost. The objective of this research is to evaluate a metric that is independent of the amount and the evolution of radiative forcing, hence facilitating comparison between the two sets for surface temperature over eastern North America. The link between CMIP3 and CMIP5 data sets is explored spatially and locally (using the ratio of local to global temperatures) through the use of regional warming patterns, a relationship between the grid-box and the global mean temperature change for a certa...
ABSTRACT Anthropogenic greenhouse gas emissions that induce changes in the Earth’s climate affect... more ABSTRACT Anthropogenic greenhouse gas emissions that induce changes in the Earth’s climate affect particular variables and locations differently. A key part of this difference is the timescale at which this change takes place, which will eventually have important consequences for adaptation requirements. This idea of timescale associated with climate change has been used several times in the past to estimate the urgency of adaptation in particular regions. The definition of climate-change timescale is, however, not unique. For example, we can think of it in terms of an expected trend (e.g. in temperature) reaching a given threshold, or think of it in terms of the time it may take this trend to become statistically significant. We may also wonder about the validity of this speculation given that, due to natural variability, the expected trend may in fact not be realized. In this article we explore alternative ways of defining the timescale of climate-change, compare their properties, and illustrate them with an example for the case of projected surface temperature over North America. It is shown that these timescales are analytically related but may differ substantially in magnitude under certain conditions. In particular, it is shown that climate change impact on vulnerable systems may arrive before statistical detection of the variable’s trend takes place. This fact may have implications on how climate change impacts are seen by those with diverging interests.
ABSTRACT Extratropical cyclones (ETCs) play a crucial role in determining the climate in a large ... more ABSTRACT Extratropical cyclones (ETCs) play a crucial role in determining the climate in a large part of the world. For this reason, climate models’ ability to reproduce ETCs’ characteristics (such as track location and development and decay regions) is of great importance. ETC tracking algorithms are sophisticated diagnostic tools that have been used extensively to evaluate models’ ability to simulate ETCs. In general, these algorithms have been developed and applied to coarse resolution global datasets such as global climate models and reanalyses. As regional climate models (RCMs) mature, the potential for tracking ETCs at considerably higher resolutions has naturally become attractive. Application of ETC tracking algorithms to RCM-produced datasets, however, introduces additional challenges. In order to investigate these challenges, we compare ETC tracking results of a simulation produced by the Canadian Regional Climate Model (CRCM) over North America at a 45-km resolution driven by ECMWF ERA-Interim, with the results obtained directly from the driving reanalyses. The ERA-Interim data is treated in three different ways applying spatial smoothing, the tracking algorithm, and the extraction of the regional grid in a different order, so that individual sources of error can be identified. It is shown that the mere existence of boundaries in the regional domain of the CRCM affects tracking results not only near the boundaries but also well within the domain. To a lesser extent, the use of different spatial smoothing techniques also affects the number of tracked ETCs. However, even after accounting for these artifacts, the CRCM produces a lower ETC count than the driving dataset. This underestimation of the tracking statistics might be related to known CRCM biases, or to some problems with the surface representation at 45-km resolution. Nevertheless, it is concluded that RCMs are a suitable choice for ETC trajectory studies, but only when handled carefully and used over large domains targeting the cyclone track of interest.
ABSTRACT The release of new data constituting the Coupled Model Intercomparison Project—Phase 5 (... more ABSTRACT The release of new data constituting the Coupled Model Intercomparison Project—Phase 5 (CMIP5) database is an important event in both climate science and climate services issues. Although users’ eagerness for a fast transition from CMIP3 to CMIP5 is expected, this change implies some challenges for climate information providers. The main reason is that the two sets of experiments were performed in different ways regarding radiative forcing and hence continuity between both datasets is partially lost. The objective of this research is to evaluate a metric that is independent of the amount and the evolution of radiative forcing, hence facilitating comparison between the two sets for surface temperature over eastern North America. The link between CMIP3 and CMIP5 data sets is explored spatially and locally (using the ratio of local to global temperatures) through the use of regional warming patterns, a relationship between the grid-box and the global mean temperature change for a certain time frame. Here, we show that local to global ratios are effective tools in making climate change information between the two sets comparable. As a response to the global mean temperature change, both CMIP experiments show very similar warming patterns, trends, and climate change uncertainty for both winter and summer. Sensitivity of the models to radiative forcing is not assessed. Real inter-model differences remain the largest source of uncertainty when calculating warming patterns as well as spatially-based patterns for the pattern scaling approach. This relationship between the datasets, which may escape users when they are provided with a single radiative forcing pathway, needs to be stressed by climate information providers.
The Canadian Regional Climate Model (CRCM) can be used in a simulation mode where it is driven by... more The Canadian Regional Climate Model (CRCM) can be used in a simulation mode where it is driven by objective analyses. In such mode, the model can be validated using various observational datasets. We present an investigation of the CRCM's surface hydrology from a three-year simulation conducted over the Quebec/Labrador territory. In the experiment, the CRCM was run at a 30 km horizontal grid-point spacing on a 100X100 point domain and driven by NCEP (National Center for Environmental Protection) atmospheric objective analyses for the period from June 1992 to May 1995. The CRCM's regional hydrologic budget over a series of catchment basins is investigated and validated through comparison with observations of precipitation, screen temperature, snow cover and runoff data. The model's output is also compared to evaporation data. Spatial analysis of the CRCM's annual runoff shows that the model is in good agreement with basin observations although its precipitation and surface evaporation during summer months are generally too important. On the seasonal scale, the CRCM captures the main features of the annual cycle, and in particular the snow cover accumulation, which is a major element of the hydrologic cycle with its spring melt reaching up to 50% of the annual runoff. Furthermore, investigation of the CRCM's daily precipitation characteristics and comparison with observations provides a more detailed picture of the model's precipitation behavior. Finally, results presented from sensitivity tests in regards to the model's resolution and its domain location help define the set-up for the next CRCM experiment.
This paper discusses the surface hydrology of a two-year simulation conducted over the Québec/Lab... more This paper discusses the surface hydrology of a two-year simulation conducted over the Québec/Labrador territory with the Canadian Regional Climate Model (CRCM). The CRCM was driven by NCEP (National Center for Environmental Protection) atmospheric objective analyses and was run at a 30 km horizontal grid-point spacing. Model results are compared with available observations for the period from June 1992 to
The release of new data constituting the Coupled Model Intercomparison Project—Phase 5 (CMIP5) da... more The release of new data constituting the Coupled Model Intercomparison Project—Phase 5 (CMIP5) database is an important event in both climate science and climate services issues. Although users’ eagerness for a fast transition from CMIP3 to CMIP5 is expected, this change implies some challenges for climate information providers. The main reason is that the two sets of experiments were performed in different ways regarding radiative forcing and hence continuity between both datasets is partially lost. The objective of this research is to evaluate a metric that is independent of the amount and the evolution of radiative forcing, hence facilitating comparison between the two sets for surface temperature over eastern North America. The link between CMIP3 and CMIP5 data sets is explored spatially and locally (using the ratio of local to global temperatures) through the use of regional warming patterns, a relationship between the grid-box and the global mean temperature change for a certa...
ABSTRACT Anthropogenic greenhouse gas emissions that induce changes in the Earth’s climate affect... more ABSTRACT Anthropogenic greenhouse gas emissions that induce changes in the Earth’s climate affect particular variables and locations differently. A key part of this difference is the timescale at which this change takes place, which will eventually have important consequences for adaptation requirements. This idea of timescale associated with climate change has been used several times in the past to estimate the urgency of adaptation in particular regions. The definition of climate-change timescale is, however, not unique. For example, we can think of it in terms of an expected trend (e.g. in temperature) reaching a given threshold, or think of it in terms of the time it may take this trend to become statistically significant. We may also wonder about the validity of this speculation given that, due to natural variability, the expected trend may in fact not be realized. In this article we explore alternative ways of defining the timescale of climate-change, compare their properties, and illustrate them with an example for the case of projected surface temperature over North America. It is shown that these timescales are analytically related but may differ substantially in magnitude under certain conditions. In particular, it is shown that climate change impact on vulnerable systems may arrive before statistical detection of the variable’s trend takes place. This fact may have implications on how climate change impacts are seen by those with diverging interests.
ABSTRACT Extratropical cyclones (ETCs) play a crucial role in determining the climate in a large ... more ABSTRACT Extratropical cyclones (ETCs) play a crucial role in determining the climate in a large part of the world. For this reason, climate models’ ability to reproduce ETCs’ characteristics (such as track location and development and decay regions) is of great importance. ETC tracking algorithms are sophisticated diagnostic tools that have been used extensively to evaluate models’ ability to simulate ETCs. In general, these algorithms have been developed and applied to coarse resolution global datasets such as global climate models and reanalyses. As regional climate models (RCMs) mature, the potential for tracking ETCs at considerably higher resolutions has naturally become attractive. Application of ETC tracking algorithms to RCM-produced datasets, however, introduces additional challenges. In order to investigate these challenges, we compare ETC tracking results of a simulation produced by the Canadian Regional Climate Model (CRCM) over North America at a 45-km resolution driven by ECMWF ERA-Interim, with the results obtained directly from the driving reanalyses. The ERA-Interim data is treated in three different ways applying spatial smoothing, the tracking algorithm, and the extraction of the regional grid in a different order, so that individual sources of error can be identified. It is shown that the mere existence of boundaries in the regional domain of the CRCM affects tracking results not only near the boundaries but also well within the domain. To a lesser extent, the use of different spatial smoothing techniques also affects the number of tracked ETCs. However, even after accounting for these artifacts, the CRCM produces a lower ETC count than the driving dataset. This underestimation of the tracking statistics might be related to known CRCM biases, or to some problems with the surface representation at 45-km resolution. Nevertheless, it is concluded that RCMs are a suitable choice for ETC trajectory studies, but only when handled carefully and used over large domains targeting the cyclone track of interest.
ABSTRACT The release of new data constituting the Coupled Model Intercomparison Project—Phase 5 (... more ABSTRACT The release of new data constituting the Coupled Model Intercomparison Project—Phase 5 (CMIP5) database is an important event in both climate science and climate services issues. Although users’ eagerness for a fast transition from CMIP3 to CMIP5 is expected, this change implies some challenges for climate information providers. The main reason is that the two sets of experiments were performed in different ways regarding radiative forcing and hence continuity between both datasets is partially lost. The objective of this research is to evaluate a metric that is independent of the amount and the evolution of radiative forcing, hence facilitating comparison between the two sets for surface temperature over eastern North America. The link between CMIP3 and CMIP5 data sets is explored spatially and locally (using the ratio of local to global temperatures) through the use of regional warming patterns, a relationship between the grid-box and the global mean temperature change for a certain time frame. Here, we show that local to global ratios are effective tools in making climate change information between the two sets comparable. As a response to the global mean temperature change, both CMIP experiments show very similar warming patterns, trends, and climate change uncertainty for both winter and summer. Sensitivity of the models to radiative forcing is not assessed. Real inter-model differences remain the largest source of uncertainty when calculating warming patterns as well as spatially-based patterns for the pattern scaling approach. This relationship between the datasets, which may escape users when they are provided with a single radiative forcing pathway, needs to be stressed by climate information providers.
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Papers by Anne Frigon