Norman Miller | University of California, Berkeley (original) (raw)
Papers by Norman Miller
Journal of Applied Meteorology and Climatology, 2008
ABSTRACT Over the twenty-first century, the frequency of extreme-heat events for major cities in ... more ABSTRACT Over the twenty-first century, the frequency of extreme-heat events for major cities in heavily air conditioned California is projected to increase rapidly. Extreme heat is defined here as the temperature threshold for the 90th-percentile excedence probability (T90) of the local warmest summer days under the current climate. Climate projections from three atmosphere-ocean general circulation models, with a range of low to midhigh temperature sensitivity forced by the Special Report on Emission Scenarios higher, middle, and lower emission scenarios, indicate that these increases in temperature extremes and variance are projected to exceed the rate of increase in mean temperature. Overall, projected increases in extreme heat under the higher A1fi emission scenario by 2070-99 tend to be 20%-30% higher than those projected under the lower B1 emission scenario. Increases range from approximately 2 times the present-day number of days for inland California cities (e.g., Sacramento and Fresno), up to 4 times for previously temperate coastal cities (e.g., Los Angeles and San Diego), implying that present-day "heat wave" conditions may dominate summer months--and patterns of electricity demand--in the future. When the projected extreme heat and observed relationships between high temperature and electricity demand for California are mapped onto current availability, maintaining technology and population constant for demand-side calculations, a potential for electricity deficits as high as 17% during T90 peak electricity demand periods is found. Similar increases in extreme-heat days are likely for other southwestern U.S. urban locations, as well as for large cities in developing nations with rapidly increasing electricity demands. In light of the electricity response to recent extreme-heat events, such as the July 2006 heat waves in California, Missouri, and New York, these results suggest that future increases in peak electricity demand will challenge current transmission and supply methods as well as future planned supply capacities when population and income growth are taken into account.
Hydrological Processes, 2006
Snow anomalies in the western USA have a significant impact on water availability, and hence have... more Snow anomalies in the western USA have a significant impact on water availability, and hence have been widely investigated by many researchers. This study focuses on how anomalous atmospheric circulation affects snowpack accumulation in the western USA. Our results indicate that the mid-latitude atmospheric circulation anomalies induced by the El Niño-Southern Oscillation (ENSO) tend to drive winter precipitation shifts, leading
AGU Spring Meeting Abstracts, May 1, 2008
AGU Fall Meeting Abstracts, Dec 1, 2009
The Community Land Model version 3.5 (CLM3.5) developed by the National Center for Atmospheric Re... more The Community Land Model version 3.5 (CLM3.5) developed by the National Center for Atmospheric Research (NCAR) was coupled into the Weather Research and Forecasting (WRF) Model version 3.0. The performance of WRF3.0-CLM3.5 in simulating snowpack was extensively evaluated with in-situ observations from a mountainous site called Col de Porte, located in northern Alps region of France, and the Columbia River Basin, located in the northwestern United States. CLM3.5 was configured with a five-layer snow scheme, and includes snow compaction and liquid water transfer processes, and a sophisticated snow albedo scheme. WRF3.0-CLM3.5 was forced with the National Center for Atmospheric Research/National Centers for Environmental Prediction Reanalysis data to simulate for the 1988-1989 snow season for the Col de Porte site and the 2001-2002 season for the Columbia River Basin, with 60km-20km two-way nested domains. The initial simulations show that WRF3.0-CLM3.5 significantly improves snow simulations when compared to those produced with the WRF3.0 coupled to the Noah land surface scheme at the both study sites. However, WRF3.0-CLM3.5 still tends to underestimate the observed snowpack. Calibration with the observed data from the Col de Porte site indicates that the snow water content bias mainly results from stronger, high elevation incoming solar radiation. An adjustment for the radiation scheme in WRF3.0 was made to reduce the incoming radiation to better fit with the observations. This adjustment improves snow simulations at both Col de Porte site and the Columbia River Basin. Additional offline snow simulations with CLM3.5 driven with observed forcing data were performed at the Col de Porte site. These offline simulations are compared to the results produced with the coupled WRF3.0-CLM3.5. Through this comparison, snow-atmosphere interactions are quantitatively indentified. The improved snow simulations in WRF3.0-CLM3.5 will benefit regional hydro-climate research and forecasts.
Journal of Hydrometeorology, Apr 1, 2007
Monthly Weather Review, Apr 1, 2012
Theoretical and Applied Climatology, Oct 20, 2010
Global and Planetary Change, Feb 1, 2008
Hydrological Processes, Jun 2, 2004
Hydrological Processes, Feb 1, 2011
The land surface scheme (NOAH) in the current version of the Penn State-National Center for Atmos... more The land surface scheme (NOAH) in the current version of the Penn State-National Center for Atmospheric Research (NCAR) fifth generation Mesoscale Model (MM5) insufficiently treats snowmelt runoff over the Sierra Nevada region due to an insufficient treatment of the snow processes. To improve snowmelt runoff simulation, we have coupled the newly released NCAR Community Land Model version 3 (CLM3) to MM5. CLM3 physically describes the mass and heat transfer within the snowpack using 5 snow layers that include liquid water and solid ice. Interactions among the snow, soil, and vegetation are a function of the CLM3 mass and energy equations. Additionally, a river routing scheme has been adopted in CLM3 to better describe the runoff hydrograph. Several observed datasets from different sources were used to evaluate the model output, including snow depth, temperature, and precipitation from the automated Snowpack Telemetry system, snow cover and vegetation indices from the MODIS satellite data, and streamflow data from the U.S. Geological Survey. In this presentation, we describe the results from an MM5-CLM3 integration from April 1 to June 30, 1998 with 60 km and 20 km nested domains. The results indicate that the coupled model significantly improves the simulation of the snow mass, resulting in a better description of the runoff in the Sierra Nevada region. The application of the river routing scheme further improves the runoff hydrograph simulation. Meanwhile, MM5-CLM3 produces better simulations for the surface air temperature and precipitation as it has more realistic descriptions of the surface energy balance and hydrological cycle when compared to the original version of MM5 with the NOAH land surface model. The coupling of the advanced CLM3 with MM5 significantly improves the regional hydroclimate and water resources predictability.
Geophysical Research Letters, 2005
Geophysical Research Letters, Dec 1, 2004
This paper was prepared as the result of work sponsored by the California Energy Commission (Ener... more This paper was prepared as the result of work sponsored by the California Energy Commission (Energy Commission) and the California Environmental Protection Agency (Cal/EPA). It does not necessarily represent the views of the Energy Commission, Cal/EPA, their employees, or the State of California. The Energy Commission, Cal/EPA, the State of California, their employees, contractors, and subcontractors make no warrant, express or implied, and assume no legal liability for the information in this paper; nor does any party represent that the uses of this information will not infringe upon privately owned rights. This paper has not been approved or disapproved by the California Energy Commission or Cal/EPA, nor has the California Energy Commission or Cal/EPA passed upon the accuracy or adequacy of the information in this paper. F IN A L P A P E R
Ecological Modelling, Aug 1, 2010
Journal of Applied Meteorology and Climatology, 2008
ABSTRACT Over the twenty-first century, the frequency of extreme-heat events for major cities in ... more ABSTRACT Over the twenty-first century, the frequency of extreme-heat events for major cities in heavily air conditioned California is projected to increase rapidly. Extreme heat is defined here as the temperature threshold for the 90th-percentile excedence probability (T90) of the local warmest summer days under the current climate. Climate projections from three atmosphere-ocean general circulation models, with a range of low to midhigh temperature sensitivity forced by the Special Report on Emission Scenarios higher, middle, and lower emission scenarios, indicate that these increases in temperature extremes and variance are projected to exceed the rate of increase in mean temperature. Overall, projected increases in extreme heat under the higher A1fi emission scenario by 2070-99 tend to be 20%-30% higher than those projected under the lower B1 emission scenario. Increases range from approximately 2 times the present-day number of days for inland California cities (e.g., Sacramento and Fresno), up to 4 times for previously temperate coastal cities (e.g., Los Angeles and San Diego), implying that present-day "heat wave" conditions may dominate summer months--and patterns of electricity demand--in the future. When the projected extreme heat and observed relationships between high temperature and electricity demand for California are mapped onto current availability, maintaining technology and population constant for demand-side calculations, a potential for electricity deficits as high as 17% during T90 peak electricity demand periods is found. Similar increases in extreme-heat days are likely for other southwestern U.S. urban locations, as well as for large cities in developing nations with rapidly increasing electricity demands. In light of the electricity response to recent extreme-heat events, such as the July 2006 heat waves in California, Missouri, and New York, these results suggest that future increases in peak electricity demand will challenge current transmission and supply methods as well as future planned supply capacities when population and income growth are taken into account.
Hydrological Processes, 2006
Snow anomalies in the western USA have a significant impact on water availability, and hence have... more Snow anomalies in the western USA have a significant impact on water availability, and hence have been widely investigated by many researchers. This study focuses on how anomalous atmospheric circulation affects snowpack accumulation in the western USA. Our results indicate that the mid-latitude atmospheric circulation anomalies induced by the El Niño-Southern Oscillation (ENSO) tend to drive winter precipitation shifts, leading
AGU Spring Meeting Abstracts, May 1, 2008
AGU Fall Meeting Abstracts, Dec 1, 2009
The Community Land Model version 3.5 (CLM3.5) developed by the National Center for Atmospheric Re... more The Community Land Model version 3.5 (CLM3.5) developed by the National Center for Atmospheric Research (NCAR) was coupled into the Weather Research and Forecasting (WRF) Model version 3.0. The performance of WRF3.0-CLM3.5 in simulating snowpack was extensively evaluated with in-situ observations from a mountainous site called Col de Porte, located in northern Alps region of France, and the Columbia River Basin, located in the northwestern United States. CLM3.5 was configured with a five-layer snow scheme, and includes snow compaction and liquid water transfer processes, and a sophisticated snow albedo scheme. WRF3.0-CLM3.5 was forced with the National Center for Atmospheric Research/National Centers for Environmental Prediction Reanalysis data to simulate for the 1988-1989 snow season for the Col de Porte site and the 2001-2002 season for the Columbia River Basin, with 60km-20km two-way nested domains. The initial simulations show that WRF3.0-CLM3.5 significantly improves snow simulations when compared to those produced with the WRF3.0 coupled to the Noah land surface scheme at the both study sites. However, WRF3.0-CLM3.5 still tends to underestimate the observed snowpack. Calibration with the observed data from the Col de Porte site indicates that the snow water content bias mainly results from stronger, high elevation incoming solar radiation. An adjustment for the radiation scheme in WRF3.0 was made to reduce the incoming radiation to better fit with the observations. This adjustment improves snow simulations at both Col de Porte site and the Columbia River Basin. Additional offline snow simulations with CLM3.5 driven with observed forcing data were performed at the Col de Porte site. These offline simulations are compared to the results produced with the coupled WRF3.0-CLM3.5. Through this comparison, snow-atmosphere interactions are quantitatively indentified. The improved snow simulations in WRF3.0-CLM3.5 will benefit regional hydro-climate research and forecasts.
Journal of Hydrometeorology, Apr 1, 2007
Monthly Weather Review, Apr 1, 2012
Theoretical and Applied Climatology, Oct 20, 2010
Global and Planetary Change, Feb 1, 2008
Hydrological Processes, Jun 2, 2004
Hydrological Processes, Feb 1, 2011
The land surface scheme (NOAH) in the current version of the Penn State-National Center for Atmos... more The land surface scheme (NOAH) in the current version of the Penn State-National Center for Atmospheric Research (NCAR) fifth generation Mesoscale Model (MM5) insufficiently treats snowmelt runoff over the Sierra Nevada region due to an insufficient treatment of the snow processes. To improve snowmelt runoff simulation, we have coupled the newly released NCAR Community Land Model version 3 (CLM3) to MM5. CLM3 physically describes the mass and heat transfer within the snowpack using 5 snow layers that include liquid water and solid ice. Interactions among the snow, soil, and vegetation are a function of the CLM3 mass and energy equations. Additionally, a river routing scheme has been adopted in CLM3 to better describe the runoff hydrograph. Several observed datasets from different sources were used to evaluate the model output, including snow depth, temperature, and precipitation from the automated Snowpack Telemetry system, snow cover and vegetation indices from the MODIS satellite data, and streamflow data from the U.S. Geological Survey. In this presentation, we describe the results from an MM5-CLM3 integration from April 1 to June 30, 1998 with 60 km and 20 km nested domains. The results indicate that the coupled model significantly improves the simulation of the snow mass, resulting in a better description of the runoff in the Sierra Nevada region. The application of the river routing scheme further improves the runoff hydrograph simulation. Meanwhile, MM5-CLM3 produces better simulations for the surface air temperature and precipitation as it has more realistic descriptions of the surface energy balance and hydrological cycle when compared to the original version of MM5 with the NOAH land surface model. The coupling of the advanced CLM3 with MM5 significantly improves the regional hydroclimate and water resources predictability.
Geophysical Research Letters, 2005
Geophysical Research Letters, Dec 1, 2004
This paper was prepared as the result of work sponsored by the California Energy Commission (Ener... more This paper was prepared as the result of work sponsored by the California Energy Commission (Energy Commission) and the California Environmental Protection Agency (Cal/EPA). It does not necessarily represent the views of the Energy Commission, Cal/EPA, their employees, or the State of California. The Energy Commission, Cal/EPA, the State of California, their employees, contractors, and subcontractors make no warrant, express or implied, and assume no legal liability for the information in this paper; nor does any party represent that the uses of this information will not infringe upon privately owned rights. This paper has not been approved or disapproved by the California Energy Commission or Cal/EPA, nor has the California Energy Commission or Cal/EPA passed upon the accuracy or adequacy of the information in this paper. F IN A L P A P E R
Ecological Modelling, Aug 1, 2010