scholarly journals Updated world map of the Köppen-Geiger climate classification

2007 ◽  
Vol 4 (2) ◽  
pp. 439-473 ◽  
Author(s):  
M. C. Peel ◽  
B. L. Finlayson ◽  
T. A. McMahon
Keyword(s):  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Monthly Precipitation ◽  
Land Area ◽  
Climate Type ◽  
Data Set ◽  
Global Data

Abstract. Although now over 100 years old, the classification of climate originally formulated by Wladimir Köppen and modified by his collaborators and successors, is still in widespread use. It is widely used in teaching school and undergraduate courses on climate. It is also still in regular use by researchers across a range of disciplines as a basis for climatic regionalisation of variables and for assessing the output of global climate models. Here we have produced a new global map of climate using the Köppen-Geiger system based on a large global data set of long-term monthly precipitation and temperature station time series. Climatic variables used in the Köppen-Geiger system were calculated at each station and interpolated between stations using a two-dimensional (latitude and longitude) thin-plate spline with tension onto a 0.1°×0.1° grid for each continent. We discuss some problems in dealing with sites that are not uniquely classified into one climate type by the Köppen-Geiger system and assess the outcomes on a continent by continent basis. Globally the most common climate type by land area is BWh (14.2%, Hot desert) followed by Aw (11.5%, Tropical savannah). The updated world Köppen-Geiger climate map is freely available electronically at https://www.hydrol-earth-syst-sci.net/????.

scholarly journals Updated world map of the Köppen-Geiger climate classification

2007 ◽  
Vol 11 (5) ◽  
pp. 1633-1644 ◽  
Author(s):  
M. C. Peel ◽  
B. L. Finlayson ◽  
T. A. McMahon
Keyword(s):  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Monthly Precipitation ◽  
Climate Type ◽  
Data Set ◽  
Supplementary Material ◽  
Global Data

Abstract. Although now over 100 years old, the classification of climate originally formulated by Wladimir Köppen and modified by his collaborators and successors, is still in widespread use. It is widely used in teaching school and undergraduate courses on climate. It is also still in regular use by researchers across a range of disciplines as a basis for climatic regionalisation of variables and for assessing the output of global climate models. Here we have produced a new global map of climate using the Köppen-Geiger system based on a large global data set of long-term monthly precipitation and temperature station time series. Climatic variables used in the Köppen-Geiger system were calculated at each station and interpolated between stations using a two-dimensional (latitude and longitude) thin-plate spline with tension onto a 0.1°×0.1° grid for each continent. We discuss some problems in dealing with sites that are not uniquely classified into one climate type by the Köppen-Geiger system and assess the outcomes on a continent by continent basis. Globally the most common climate type by land area is BWh (14.2%, Hot desert) followed by Aw (11.5%, Tropical savannah). The updated world Köppen-Geiger climate map is freely available electronically in the Supplementary Material Section.

scholarly journals Surface matters: limitations of CALIPSO V3 aerosol typing in coastal regions

2014 ◽  
Vol 7 (7) ◽  
pp. 2061-2072 ◽  
Author(s):  
T. Kanitz ◽  
A. Ansmann ◽  
A. Foth ◽  
P. Seifert ◽  
U. Wandinger ◽  
...  
Keyword(s):  
Data Analysis ◽  
Climate Models ◽  
Global Climate ◽  
Coastal Areas ◽  
Global Climate Models ◽  
Important Input ◽  
High Fraction ◽  
Ground Based Lidar

Abstract. In the CALIPSO data analysis, surface type (land/ocean) is used to augment the aerosol characterization. However, this surface-dependent aerosol typing prohibits a correct classification of marine aerosol over land that is advected from ocean to land. This might result in a systematic overestimation of the particle extinction coefficient and of the aerosol optical thickness (AOT) of up to a factor of 3.5 over land in coastal areas. We present a long-term comparison of CALIPSO and ground-based lidar observations of the aerosol conditions in the coastal environment of southern South America (Punta Arenas, Chile, 53° S), performed in December 2009–April 2010. Punta Arenas is almost entirely influenced by marine particles throughout the year, indicated by a rather low AOT of 0.02–0.04. However, we found an unexpectedly high fraction of continental aerosol in the aerosol types inferred by means of CALIOP observations and, correspondingly, too high values of particle extinction. Similar features of the CALIOP data analysis are presented for four other coastal areas around the world. Since CALIOP data serve as important input for global climate models, the influence of this systematic error was estimated by means of simplified radiative-transfer calculations.

scholarly journals A long-term (2002 to 2017) record of closed-path and open-path eddy covariance CO<sub>2</sub> net ecosystem exchange fluxes from the Siberian Arctic

2019 ◽  
Vol 11 (1) ◽  
pp. 221-240 ◽  
Author(s):  
David Holl ◽  
Christian Wille ◽  
Torsten Sachs ◽  
Peter Schreiber ◽  
Benjamin R. K. Runkle ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Eddy Covariance ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Closed Path ◽  
Data Set ◽  
Open Path ◽  
Siberian Arctic

Abstract. Ground-based observations of land–atmosphere fluxes are necessary to progressively improve global climate models. Observed data can be used for model evaluation and to develop or tune process models. In arctic permafrost regions, climate–carbon feedbacks are amplified. Therefore, increased efforts to better represent these regions in global climate models have been made in recent years. We present a multi-annual time series of land–atmosphere carbon dioxide fluxes measured in situ with the eddy covariance technique in the Siberian Arctic (72∘22′ N, 126∘30′ E). The site is part of the international network of eddy covariance flux observation stations (FLUXNET; site ID: Ru-Sam). The data set includes consistently processed fluxes based on concentration measurements of closed-path and open-path gas analyzers. With parallel records from both sensor types, we were able to apply a site-specific correction to open-path fluxes. This correction is necessary due to a deterioration of data, caused by heat generated by the electronics of open-path gas analyzers. Parameterizing this correction for subperiods of distinct sensor setups yielded good agreement between open- and closed-path fluxes. We compiled a long-term (2002 to 2017) carbon dioxide flux time series that we additionally gap-filled with a standardized approach. The data set was uploaded to the Pangaea database and can be accessed through https://doi.org/10.1594/PANGAEA.892751.

scholarly journals Global climatology and trends in convective environments from ERA5 and rawinsonde data

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mateusz Taszarek ◽  
John T. Allen ◽  
Mattia Marchio ◽  
Harold E. Brooks
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Global Climate ◽  
Convective Available Potential Energy ◽  
Global Climate Models ◽  
Convective Precipitation ◽  
The Past ◽  
The Tropics ◽  
Rawinsonde Data

AbstractGlobally, thunderstorms are responsible for a significant fraction of rainfall, and in the mid-latitudes often produce extreme weather, including large hail, tornadoes and damaging winds. Despite this importance, how the global frequency of thunderstorms and their accompanying hazards has changed over the past 4 decades remains unclear. Large-scale diagnostics applied to global climate models have suggested that the frequency of thunderstorms and their intensity is likely to increase in the future. Here, we show that according to ERA5 convective available potential energy (CAPE) and convective precipitation (CP) have decreased over the tropics and subtropics with simultaneous increases in 0–6 km wind shear (BS06). Conversely, rawinsonde observations paint a different picture across the mid-latitudes with increasing CAPE and significant decreases to BS06. Differing trends and disagreement between ERA5 and rawinsondes observed over some regions suggest that results should be interpreted with caution, especially for CAPE and CP across tropics where uncertainty is the highest and reliable long-term rawinsonde observations are missing.

scholarly journals Back to the Future: Using Long-Term Observational and Paleo-Proxy Reconstructions to Improve Model Projections of Antarctic Climate

Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 255 ◽  
Author(s):  
Thomas J. Bracegirdle ◽  
Florence Colleoni ◽  
Nerilie J. Abram ◽  
Nancy A. N. Bertler ◽  
Daniel A. Dixon ◽  
...  
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Global Climate ◽  
Ice Core ◽  
Global Climate Models ◽  
Climate Projections ◽  
Past Performance ◽  
Wide Range ◽  
Proxy Reconstructions

Quantitative estimates of future Antarctic climate change are derived from numerical global climate models. Evaluation of the reliability of climate model projections involves many lines of evidence on past performance combined with knowledge of the processes that need to be represented. Routine model evaluation is mainly based on the modern observational period, which started with the establishment of a network of Antarctic weather stations in 1957/58. This period is too short to evaluate many fundamental aspects of the Antarctic and Southern Ocean climate system, such as decadal-to-century time-scale climate variability and trends. To help address this gap, we present a new evaluation of potential ways in which long-term observational and paleo-proxy reconstructions may be used, with a particular focus on improving projections. A wide range of data sources and time periods is included, ranging from ship observations of the early 20th century to ice core records spanning hundreds to hundreds of thousands of years to sediment records dating back 34 million years. We conclude that paleo-proxy records and long-term observational datasets are an underused resource in terms of strategies for improving Antarctic climate projections for the 21st century and beyond. We identify priorities and suggest next steps to addressing this.

scholarly journals Varying soil moisture-atmosphere feedbacks explain divergent temperature extremes and precipitation projections in Central Europe

2018 ◽  
Author(s):  
Martha M. Vogel ◽  
Jakob Zscheischler ◽  
Sonia I. Seneviratne
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Central Europe ◽  
Climate Models ◽  
Global Climate ◽  
Summer Precipitation ◽  
Global Climate Models ◽  
Temperature Extremes ◽  
Extreme Temperatures

Abstract. The frequency and intensity of climate extremes is expected to increase in many regions due to anthropogenic climate change. In Central Europe extreme temperatures are projected to change more strongly than global mean temperatures and soil moisture-temperature feedbacks significantly contribute to this regional amplification. Because of their strong societal, ecological and economic impacts, robust projections of temperature extremes are needed. Unfortunately, in current model projections, temperature extremes in Central Europe are prone to large uncertainties. In order to understand and potentially reduce uncertainties of extreme temperatures projections in Europe, we analyze global climate models from the CMIP5 ensemble for the business-as-usual high-emission scenario (RCP8.5). We find a divergent behavior in long-term projections of summer precipitation until the end of the 21st century, resulting in a trimodal distribution of precipitation (wet, dry and very dry). All model groups show distinct characteristics for summer latent heat flux, top soil moisture, and temperatures on the hottest day of the year (TXx), whereas for net radiation and large-scale circulation no clear trimodal behavior is detectable. This suggests that different land-atmosphere coupling strengths may be able to explain the uncertainties in temperature extremes. Constraining the full model ensemble with observed present-day correlations between summer precipitation and TXx excludes most of the very dry and dry models. In particular, the very dry models tend to overestimate the negative coupling between precipitation and TXx, resulting in a too strong warming. This is particularly relevant for global warming levels above 2 °C. The analysis allows for the first time to substantially reduce uncertainties in the projected changes of TXx in global climate models. Our results suggest that long-term temperature changes in TXx in Central Europe are about 20 % lower than projected by the multi-model median of the full ensemble. In addition, mean summer precipitation is found to be more likely to stay close to present-day levels. These results are highly relevant for improving estimates of regional climate-change impacts including heat stress, water supply and crop failure for Central Europe.

The Double-ITCZ Bias in CMIP6 Models

2020 ◽  
Author(s):  
Baijun Tian
Keyword(s):  
Climate Models ◽  
Global Climate ◽  
Coupled Model ◽  
Global Climate Models ◽  
Cmip5 Models ◽  
Tropical Precipitation ◽  
Double Itcz ◽  
Intercomparison Project ◽  
Fully Coupled

&lt;p&gt;The double-Intertropical Convergence Zone (ITCZ) bias is one of the most outstanding problems in climate models. This study seeks to examine the double-ITCZ bias in the latest state-of-the-art fully coupled global climate models that participated in Coupled Model Intercomparison Project (CMIP) Phase 6 (CMIP6) in comparison to their previous generations (CMIP3 and CMIP5 models). To that end, we have analyzed the long-term annual mean tropical precipitation distributions and several precipitation bias indices that quantify the double-ITCZ biases in 75 climate models including 24 CMIP3 models, 25 CMIP3 models, and 26 CMIP6 models. We find that the double-ITCZ bias and its big inter-model spread persist in CMIP6 models but the double-ITCZ bias is slightly reduced from CMIP3 or CMIP5 models to CMIP6 models.&lt;/p&gt;

scholarly journals Terrestrial Water Loss at Night: Global Relevance from Observations and Climate Models

2019 ◽  
Author(s):  
Ryan S. Padrón ◽  
Lukas Gudmundsson ◽  
Dominik Michel ◽  
Sonia I. Seneviratne
Keyword(s):  
Water Loss ◽  
Vapor Pressure Deficit ◽  
Climate Models ◽  
Water Cycle ◽  
Global Climate ◽  
Global Climate Models ◽  
Land Area ◽  
Nocturnal Transpiration ◽  
Terrestrial Water ◽  
Eddy Covariance Measurements

Abstract. Nocturnal water loss (NWL) from the surface into the atmosphere is often overlooked because of the absence of solar radiation to drive evapotranspiration and the measuring difficulties involved. However, there is growing evidence that suggests NWL – and particularly nocturnal transpiration – represents a considerable fraction of the daily values. Here we provide a global overview of the characteristics of NWL based on latent heat flux estimates from the FLUXNET2015 dataset, as well as from simulations of global climate models. Eddy-covariance measurements at 99 sites indicate that on average NWL represents 6.3 % of total evapotranspiration. There are six sites where NWL is higher than 15 %; these are mountain forests with considerable NWL during winter related to snowy and windy conditions. Higher vapor pressure deficit, wind speed and soil moisture are related to higher NWL, although this is not consistent across all sites. On the other hand, the global multi-model mean of terrestrial NWL is 7.9 % of total evapotranspiration. The spread of the model ensemble, however, is greater than 20 % over 70 % of the land area. Finally, the multi-model mean of future projections indicates an increase of NWL everywhere by an average of 1.8 %, but the spread between models at individual locations is often twice as large at least. Overall, this study highlights the relevance of water loss during the night and opens the door to explore its influence on the water cycle and the climate system under present and future conditions.

scholarly journals Observed and Projected Future Shifts of Climatic Zones in Europe and Their Use to Visualize Climate Change Information

2010 ◽  
Vol 2 (2) ◽  
pp. 148-167 ◽  
Author(s):  
Kirsti Jylhä ◽  
Heikki Tuomenvirta ◽  
Kimmo Ruosteenoja ◽  
Hanna Niemi-Hugaerts ◽  
Krista Keisu ◽  
...  
Keyword(s):  
Climate Change ◽  
Questionnaire Survey ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Climate Type ◽  
Climatic Zones ◽  
Average Percentage ◽  
Climate Change Information ◽  
Projected Changes

Abstract A Web site questionnaire survey in Finland suggested that maps illustrating projected shifts of Köppen climatic zones are an effective visualization tool for disseminating climate change information. The climate classification is based on seasonal cycles of monthly-mean temperature and precipitation, and it divides Europe and its adjacent land areas into tundra, boreal, temperate, and dry climate types. Projections of future changes in the climatic zones were composed using multimodel mean projections based on simulations performed with 19 global climate models. The projections imply that, depending on the greenhouse gas scenarios, about half or possibly even two-thirds of the study domain will be affected by shifts toward a warmer or drier climate type during this century. The projected changes within the next few decades are chiefly located near regions where shifts in the borders of the zones have already occurred during the period 1950–2006. The questionnaire survey indicated that the information regarding the shifting climatic zones as disseminated by the maps was generally interpreted correctly, with the average percentage of correct answers being 86%. Additional examples of the use of the climatic zones to communicate climate change information to the public are included.

scholarly journals Differences between downscaling with spectral and grid nudging using WRF

2012 ◽  
Vol 12 (8) ◽  
pp. 3601-3610 ◽  
Author(s):  
P. Liu ◽  
A. P. Tsimpidi ◽  
Y. Hu ◽  
B. Stone ◽  
A. G. Russell ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Dynamical Downscaling ◽  
Global Climate ◽  
Regional Climate ◽  
Wrf Model ◽  
Global Climate Models ◽  
Small Scale ◽  
Data Set ◽  
Spectral Nudging

Abstract. Dynamical downscaling has been extensively used to study regional climate forced by large-scale global climate models. During the downscaling process, however, the simulation of regional climate models (RCMs) tends to drift away from the driving fields. Developing a solution that addresses this issue, by retaining the large scale features (from the large-scale fields) and the small-scale features (from the RCMs) has led to the development of "nudging" techniques. Here, we examine the performance of two nudging techniques, grid and spectral nudging, in the downscaling of NCEP/NCAR data with the Weather Research and Forecasting (WRF) Model. The simulations are compared against the results with North America Regional Reanalysis (NARR) data set at different scales of interest using the concept of similarity. We show that with the appropriate choice of wave numbers, spectral nudging outperforms grid nudging in the capacity of balancing the performance of simulation at the large and small scales.

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