scholarly journals On Climate Impacts of a Potential Expansion of Urban Land in Europe

2009 ◽  
Vol 48 (9) ◽  
pp. 1971-1980 ◽  
Author(s):  
K. Trusilova ◽  
M. Jung ◽  
G. Churkina
Keyword(s):  
Thermal Stress ◽  
Urban Areas ◽  
Mesoscale Model ◽  
Water Cycle ◽  
Regional Climate ◽  
Urban Land ◽  
Climate Impacts ◽  
State University ◽  
Temperature And Precipitation ◽  
Artificial Heat

Abstract Over the last two decades, a disproportional increase of urban land area in comparison with the population growth has been observed in many countries of Europe, and this trend is predicted to continue. The conversion of vegetated land into urban land leads to a higher proportion of impervious surface area, to decline and change of vegetation cover, to artificial heat sources, and therefore to changes in climate. This study focuses on the implications of the expansion of urban land for the European climate at the local and regional scales. Regional climate simulations with the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) coupled to the Town Energy Budget model are used to isolate effects of urban land expansion on temperature and precipitation. The study suggests that the expansion of current urban land by 40% would lead to an enlargement of regions affected by thermal stress by a factor of 2, whereas the intensity of the thermal stress does not change significantly. Precipitation in urban areas would be reduced by 0.2 mm day−1 in summer as a result of disturbances of the water cycle caused by urban surfaces. The area in which precipitation was altered increased nearly linearly with the urban land increment.

scholarly journals Urbanization Impacts on the Climate in Europe: Numerical Experiments by the PSU–NCAR Mesoscale Model (MM5)

2008 ◽  
Vol 47 (5) ◽  
pp. 1442-1455 ◽  
Author(s):  
K. Trusilova ◽  
M. Jung ◽  
G. Churkina ◽  
U. Karstens ◽  
M. Heimann ◽  
...  
Keyword(s):  
Land Cover ◽  
Surface Temperature ◽  
Land Surface ◽  
Urban Areas ◽  
Mesoscale Model ◽  
Urban Land ◽  
Actual State ◽  
Near Surface ◽  
Temperature And Precipitation ◽  
In The Beginning

Abstract The objective of this study is to investigate the effects of urban land on the climate in Europe on local and regional scales. Effects of urban land cover on the climate are isolated using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) with a modified land surface scheme based on the Town Energy Budget model. Two model scenarios represent responses of climate to different states of urbanization in Europe: 1) no urban areas and 2) urban land in the actual state in the beginning of the twenty-first century. By comparing the simulations of these contrasting scenarios, spatial differences in near-surface temperature and precipitation are quantified. Simulated near-surface temperatures and an urban heat island for January and July over a period of 6 yr (2000–05) agree well with corresponding measurements at selected urban areas. The conversion of rural to urban land results in statistically significant changes to precipitation and near-surface temperature over areas of the land cover perturbations. The diurnal temperature range in urbanized regions was reduced on average by 1.26° ± 0.71°C in summer and by 0.73° ± 00.54°C in winter. Inclusion of urban areas results in an increase of urban precipitation in winter (0.09 ± 00.16 mm day−1) and a precipitation reduction in summer (−0.05 ± 0.22 mm day−1).

scholarly journals Ocean-atmosphere interactions modulate irrigation's climate impacts

2016 ◽  
Author(s):  
Nir Y. Krakauer ◽  
Michael J. Puma ◽  
Benjamin I. Cook ◽  
Pierre Gentine ◽  
Larissa Nazarenko
Keyword(s):  
Water Cycle ◽  
Regional Climate ◽  
Mean Amplitude ◽  
Climate Impacts ◽  
Irrigated Agriculture ◽  
Ocean Atmosphere ◽  
Ocean Atmosphere Interaction ◽  
Atmosphere Interaction ◽  
The Tropics ◽  
Global Mean

Abstract. Numerous studies have focused on the local and regional climate effects of irrigated agriculture and other land cover and land use change (LCLUC) phenomena, but there are few studies on the role of ocean-atmosphere interaction in modulating irrigation climate impacts. Here, we compare simulations of the equilibrium effect of contemporary irrigation geographic extent and intensity on climate with and without interactive sea surface temperatures. We find that ocean-atmosphere interaction does impact the magnitude of global-mean and spatially varying climate impacts, greatly increasing their global reach. The interaction amplifies irrigation-driven standing wave patterns in the tropics and midlatitudes in our simulations, approximately doubling the global mean amplitude of surface temperature changes due to irrigation. Subject to confirmation with other models, these findings imply that LCLUC is an important contributor to climate change even in remote areas such as the Southern Ocean. Attribution studies should include interactive oceans and need to consider LCLUC, including irrigation, as a truly global forcing that affects climate and the water cycle over ocean as well as land areas.

Changes in Water Vapor Transport and the Production of Precipitation in the Eastern Fertile Crescent as a Result of Global Warming

2008 ◽  
Vol 9 (6) ◽  
pp. 1390-1401 ◽  
Author(s):  
J. P. Evans
Keyword(s):  
Global Warming ◽  
Water Vapor ◽  
Climate Model ◽  
Mesoscale Model ◽  
Regional Climate ◽  
Water Vapor Transport ◽  
State University ◽  
Storm Events ◽  
Fertile Crescent ◽  
Emissions Scenarios

Abstract This study investigates changes in the types of storm events occurring in the Fertile Crescent as a result of global warming. Regional climate model [fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5)–Noah] simulations are run for the first and last five years of the twenty-first century following the Special Report on Emissions Scenarios (SRES) A2 experiment. Then the precipitation events are classified according to the water vapor fluxes that created them. At present most of the region’s precipitation is from westerly water vapor fluxes. Results indicate that the region will increasingly get its precipitation from large events that are dominated by southerly water vapor fluxes. The increase in these events will occur in the transition seasons, especially autumn.

scholarly journals Role of climate model dynamics in estimated climate responses to anthropogenic aerosols

2019 ◽  
Vol 19 (15) ◽  
pp. 9969-9987 ◽  
Author(s):  
Kalle Nordling ◽  
Hannele Korhonen ◽  
Petri Räisänen ◽  
Muzaffer Ege Alper ◽  
Petteri Uotila ◽  
...  
Keyword(s):  
Climate Models ◽  
Regional Climate ◽  
Climate Impacts ◽  
The Arctic ◽  
Anthropogenic Aerosols ◽  
Temperature And Precipitation ◽  
Model Aerosol ◽  
Regional Temperature ◽  
Temperature Responses ◽  
Climate Responses

Abstract. Significant discrepancies remain in estimates of climate impacts of anthropogenic aerosols between different general circulation models (GCMs). Here, we demonstrate that eliminating differences in model aerosol or radiative forcing fields results in close agreement in simulated globally averaged temperature and precipitation responses in the studied GCMs. However, it does not erase the differences in regional responses. We carry out experiments of equilibrium climate response to modern-day anthropogenic aerosols using an identical representation of anthropogenic aerosol optical properties and the first indirect effect of aerosols, MACv2-SP (a simple plume implementation of the second version of the Max Planck Institute Aerosol CLimatology), in two independent climate models (NorESM, Norwegian Earth System Model, and ECHAM6). We find consistent global average temperature responses of −0.48 (±0.02) and −0.50 (±0.03) K and precipitation responses of −1.69 (±0.04) % and −1.79 (±0.05) % in NorESM1 and ECHAM6, respectively, compared to modern-day equilibrium climate without anthropogenic aerosols. However, significant differences remain between the two GCMs' regional temperature responses around the Arctic circle and the Equator and precipitation responses in the tropics. The scatter in the simulated globally averaged responses is small in magnitude when compared against literature data from modern GCMs using model intrinsic aerosols but same aerosol emissions −(0.5–1.1) K and −(1.5–3.1) % for temperature and precipitation, respectively). The Pearson correlation of regional temperature (precipitation) response in these literature model experiments with intrinsic aerosols is 0.79 (0.34). The corresponding correlation coefficient for NorESM1 and ECHAM6 runs with identical aerosols is 0.78 (0.41). The lack of improvement in correlation coefficients between models with identical aerosols and models with intrinsic aerosols implies that the spatial distribution of regional climate responses is not improved via homogenizing the aerosol descriptions in the models. Rather, differences in the atmospheric dynamic and snow/sea ice cover responses dominate the differences in regional climate responses. Hence, even if we would have perfect aerosol descriptions inside the global climate models, uncertainty arising from the differences in circulation responses between the models would likely still result in a significant uncertainty in regional climate responses.

scholarly journals A regional climate simulation over the Iberian Peninsula for the last millennium

2011 ◽  
Vol 7 (2) ◽  
pp. 451-472 ◽  
Author(s):  
J. J. Gómez-Navarro ◽  
J. P. Montávez ◽  
S. Jerez ◽  
P. Jiménez-Guerrero ◽  
R. Lorente-Plazas ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Mesoscale Model ◽  
Regional Climate ◽  
Maunder Minimum ◽  
Regional Model ◽  
Climate Simulation ◽  
Last Millennium ◽  
Data Set ◽  
Temperature And Precipitation ◽  
Proxy Reconstructions

Abstract. A high-resolution (30 km) regional paleoclimate simulation of the last millennium over the Iberian Peninsula (IP) is presented. The simulation was performed with a climate version of the mesoscale model MM5 driven by the global model ECHO-G. Both models were driven by the same reconstructions of several external forcing factors. The high spatial resolution of the regional model allows climatologists to realistically simulate many aspects of the climate in the IP, as compared to an observational data set in the reference period 1961–1990. Although the spatial-averaged values developed by the regional model are tightly driven by the boundary conditions, it is capable to develop a different realisation of the past climate at regional scales, especially in the high-frequency domain and for precipitation. This has to be considered when comparing the results of climate simulations versus proxy reconstructions. A preliminary comparison of the simulation results with reconstructions of temperature and precipitation over the IP shows good agreement in the warming trends in the last century of the simulation, although there are large disagreements in key periods such as the precipitation anomalies in the Maunder Minimum.

scholarly journals A regional climate simulation over the Iberian Peninsula for the last millennium

2010 ◽  
Vol 6 (5) ◽  
pp. 2071-2116 ◽  
Author(s):  
J. J. Gómez-Navarro ◽  
J. P. Montávez ◽  
S. Jerez ◽  
P. Jiménez-Guerrero ◽  
R. Lorente-Plazas ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Mesoscale Model ◽  
Regional Climate ◽  
Regional Model ◽  
Climate Simulation ◽  
Strong Impact ◽  
Last Millennium ◽  
Data Set ◽  
Temperature And Precipitation ◽  
Proxy Reconstructions

Abstract. In this study we present a regional paleoclimate simulation which covers the last millennium over the Iberian Peninsula (IP) with an unprecedented resolution of 30 km. The simulation was performed with a climate version of the mesoscale model MM5 coupled to the global model ECHO-G. Both experiments were driven by the same reconstructions of several external factors. The high spatial resolution of the regional model allows to simulate realistically many aspects of the climate in the IP when comparing the simulation to an observational data set in a reference period (1961–1990). Although the regional model is strongly driven by the boundary conditions, it is able to develop a different realisation of the past climate, which has a strong impact in those exercises comparing the results of climate simulations versus proxy reconstructions. A preliminary comparison of the simulation results with reconstructions of temperature and precipitation over the IP allows to recognise several aspects where both approaches agree, as well as identify the disagreements and try to point out the possible causes.

scholarly journals The effect of the thermal component change on regional climate indices in Serbia

2015 ◽  
Vol 19 (suppl. 2) ◽  
pp. 391-403 ◽  
Author(s):  
Marko Joksimovic ◽  
Mirjana Gajic ◽  
Snezana Vujadinovic ◽  
Rajko Golic ◽  
Darko Vukovic
Keyword(s):  
Time Series ◽  
Urban Areas ◽  
Climate Changes ◽  
Time Series Data ◽  
Regional Climate ◽  
Series Data ◽  
Climate Indices ◽  
Thermal Component ◽  
Temperature And Precipitation ◽  
Variable Factor

The study of climate changes is most often based on the analysis of time series of temperature and precipitation in urban areas and the increase in the emission of gases having a greenhouse effect. On the other hand, the selection of representative and relevant stations and comprehensive analysis of climate indicators lead to better and more exact assessments on climate changes at the regional level. In order to connect climate changes with agricultural, biological, socio-economic and tourism databases, the paper deals with the dynamic analysis of changes in thermal component expressed through the values of regional climate indices in four climatological stations with different geographical positions in Serbia. There are significant differences between the two time series data (1961-1990 and 1991-2013) on temperature and humidity, precipitation, insolation and wind speed. However, after using the climatic indices as a tool for assessing climate changes, the results of the study suggest the relative influence of the thermal component on the change of climate indices, with a slight increase in the index of significance for human activities. Relying on the results of this alternative approach to the study of climate changes, the fact remains that the climate is not fixed but highly variable factor that should be taken into consideration in terms of monitoring, evaluation and management of the area.

scholarly journals Regional climate hindcast simulations within EURO-CORDEX: evaluation of a WRF multi-physics ensemble

2015 ◽  
Vol 8 (3) ◽  
pp. 603-618 ◽  
Author(s):  
E. Katragkou ◽  
M. García-Díez ◽  
R. Vautard ◽  
S. Sobolowski ◽  
P. Zanis ◽  
...  
Keyword(s):  
Cloud Cover ◽  
Water Cycle ◽  
Regional Climate ◽  
Shortwave Radiation ◽  
Cold Bias ◽  
Total Cloud Cover ◽  
Model Simulations ◽  
Temperature And Precipitation ◽  
Downward Shortwave Radiation ◽  
Downward Radiation

Abstract. In the current work we present six hindcast WRF (Weather Research and Forecasting model) simulations for the EURO-CORDEX (European Coordinated Regional Climate Downscaling Experiment) domain with different configurations in microphysics, convection and radiation for the time period 1990–2008. All regional model simulations are forced by the ERA-Interim reanalysis and have the same spatial resolution (0.44°). These simulations are evaluated for surface temperature, precipitation, short- and longwave downward radiation at the surface and total cloud cover. The analysis of the WRF ensemble indicates systematic temperature and precipitation biases, which are linked to different physical mechanisms in the summer and winter seasons. Overestimation of total cloud cover and underestimation of downward shortwave radiation at the surface, mostly linked to the Grell–Devenyi convection and CAM (Community Atmosphere Model) radiation schemes, intensifies the negative bias in summer temperatures over northern Europe (max −2.5 °C). Conversely, a strong positive bias in downward shortwave radiation in summer over central (40–60%) and southern Europe mitigates the systematic cold bias over these regions, signifying a typical case of error compensation. Maximum winter cold biases are over northeastern Europe (−2.8 °C); this location suggests that land–atmosphere rather than cloud–radiation interactions are to blame. Precipitation is overestimated in summer by all model configurations, especially the higher quantiles which are associated with summertime deep cumulus convection. The largest precipitation biases are produced by the Kain–Fritsch convection scheme over the Mediterranean. Precipitation biases in winter are lower than those for summer in all model configurations (15–30%). The results of this study indicate the importance of evaluating not only the basic climatic parameters of interest for climate change applications (temperature and precipitation), but also other components of the energy and water cycle, in order to identify the sources of systematic biases, possible compensatory or masking mechanisms and suggest pathways for model improvement.

scholarly journals Role of climate model dynamics in estimated climate responses to anthropogenic aerosols

2019 ◽  
Author(s):  
Kalle Nordling ◽  
Hannele Korhonen ◽  
Petri Räisänen ◽  
Muzaffer Ege Alper ◽  
Petteri Uotila ◽  
...  
Keyword(s):  
Climate Models ◽  
Regional Climate ◽  
Correlation Coefficients ◽  
Climate Impacts ◽  
Anthropogenic Aerosols ◽  
Temperature And Precipitation ◽  
Model Aerosol ◽  
Regional Temperature ◽  
Temperature Responses ◽  
Climate Responses

Abstract. Significant discrepancies remain in estimates of climate impacts of anthropogenic aerosols between different general circulation models (GCMs). Here, we demonstrate that eliminating differences in model aerosol or radiative forcing fields results in close agreement in simulated globally averaged temperature and precipitation responses in the studied GCMs. However, it does not erase the differences in regional responses. We carry out experiments of equilibrium climate response to modern day anthropogenic aerosols using an identical representation of anthropogenic aerosol optical properties and aerosol-cloud interactions, MACv2-SP, in two independent climate models (NorESM and ECHAM6). We find consistent global average temperature responses of −0.48 K and −0.50 K and precipitation responses of −1.69 % and −1.79 % in NorESM1 and ECHAM6, respectively, compared to modern-day equilibrium climate without anthropogenic aerosols. However, significant differences remain between the two GCMs regional temperature responses around the Arctic circle and the equator and precipitation responses in the tropics. The scatter in the simulated globally averaged responses is small in magnitude when compared against literature data from modern GCMs using model intrinsic aerosols but same aerosol emissions (−(0.5–1.1) K and −(1.5–3.1) % for temperature and precipitation, respectively). The Pearson correlation of regional temperature (precipitation) response in these literature model experiments with intrinsic aerosols is 0.79 (0.34). The corresponding correlation coefficients for NorESM1 and ECHAM6 runs with identical aerosols are 0.78 (0.41). The lack of improvement in correlation coefficients between models with identical aerosols and models with intrinsic aerosols implies that the spatial distribution of regional climate responses is not improved via homogenizing the aerosol descriptions in the models. Rather, differences in the atmospheric dynamic and high latitude cloud and snow/sea ice cover responses dominate the differences in regional climate responses. Hence, further improvements in the model aerosol descriptions can be expected to have a limited value in improving our understanding of regional aerosol climate impacts, unless the dynamical cores of the climate models are improved as well.

scholarly journals Implementation of an Urban Canopy Parameterization in a Mesoscale Meteorological Model

2004 ◽  
Vol 43 (11) ◽  
pp. 1648-1665 ◽  
Author(s):  
Tanya L. Otte ◽  
Avraham Lacser ◽  
Sylvain Dupont ◽  
Jason K. S. Ching
Keyword(s):  
Urban Areas ◽  
Mesoscale Model ◽  
Potential Temperature ◽  
Urban Canopy ◽  
Real Data ◽  
State University ◽  
Meteorological Model ◽  
Fifth Generation ◽  
Data Application ◽  
Air Chemistry

Abstract An urban canopy parameterization (UCP) is implemented into the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) to improve meteorological fields in the urban boundary layer for finescale (∼1-km horizontal grid spacing) simulations. The UCP uses the drag-force approach for dynamics and a simple treatment of the urban thermodynamics to account for the effects of the urban environment. The UCP is evaluated using a real-data application for Philadelphia, Pennsylvania. The simulations show that the UCP produces profiles of wind speed, friction velocity, turbulent kinetic energy, and potential temperature that are more consistent with the observations taken in urban areas and data from idealized wind tunnel studies of urban areas than do simulations that use the roughness approach. In addition, comparisons with meteorological measurements show that the UCP simulations are superior to those that use the roughness approach. This improvement of the treatment of the urban areas in the meteorological model could have implications for simulating air chemistry processes at this scale.

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