A long-term (2002 to 2017) record of closed-path and open-path eddy covariance CO&lt;sub&gt;2&lt;/sub&gt; net ecosystem exchange fluxes from the 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.

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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

10.5194/essd-2018-98 ◽

2018 ◽

Author(s):

David Holl ◽

Christian Wille ◽

Torsten Sachs ◽

Peter Schreiber ◽

Benjamin R. K. Runkle ◽

...

Keyword(s):

Carbon Dioxide ◽

Time Series ◽

Climate Models ◽

Global Climate ◽

Carbon Dioxide Flux ◽

Global Climate Models ◽

Closed Path ◽

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 multiannual 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 carbon dioxide flux observation stations (FLUXNET, Site ID: Ru-Sam). The dataset 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 data base and can be accessed through https://doi.pangaea.de/10.1594/PANGAEA.892751.

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Updated world map of the Köppen-Geiger climate classification

Hydrology and Earth System Sciences ◽

10.5194/hess-11-1633-2007 ◽

2007 ◽

Vol 11 (5) ◽

pp. 1633-1644 ◽

Cited By ~ 4011

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.

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Open-path vs. closed-path eddy covariance measurements of the net ecosystem carbon dioxide and water vapour exchange: A long-term perspective

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2008.08.011 ◽

2009 ◽

Vol 149 (2) ◽

pp. 291-302 ◽

Cited By ~ 60

Author(s):

A HASLWANTER ◽

A HAMMERLE ◽

G WOHLFAHRT

Keyword(s):

Carbon Dioxide ◽

Water Vapour ◽

Eddy Covariance ◽

Closed Path ◽

Ecosystem Carbon ◽

Open Path ◽

Eddy Covariance Measurements

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Review on the manuscript ‘A long-term (2002 to 2017) record of closed-path and open-path eddy covariance CO2 net ecosystem exchange fluxes from the Siberian Arctic’, submitted for publication to ESSD by David Holl et al.

10.5194/essd-2018-98-rc1 ◽

2018 ◽

Author(s):

Anonymous

Keyword(s):

Eddy Covariance ◽

Net Ecosystem Exchange ◽

Closed Path ◽

Open Path ◽

Siberian Arctic

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Updated world map of the Köppen-Geiger climate classification

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-4-439-2007 ◽

2007 ◽

Vol 4 (2) ◽

pp. 439-473 ◽

Cited By ~ 1028

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

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

npj Climate and Atmospheric Science ◽

10.1038/s41612-021-00190-x ◽

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.

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

Atmospheric Measurement Techniques ◽

10.5194/amt-7-2061-2014 ◽

2014 ◽

Vol 7 (7) ◽

pp. 2061-2072 ◽

Cited By ~ 17

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.

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

Geosciences ◽

10.3390/geosciences9060255 ◽

2019 ◽

Vol 9 (6) ◽

pp. 255 ◽

Cited By ~ 6

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.

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Dried, closed-path eddy covariance method for measuring carbon dioxide flux over sea ice

Atmospheric Measurement Techniques ◽

10.5194/amt-11-6075-2018 ◽

2018 ◽

Vol 11 (11) ◽

pp. 6075-6090 ◽

Cited By ~ 4

Author(s):

Brian J. Butterworth ◽

Brent G. T. Else

Keyword(s):

Carbon Dioxide ◽

Sea Ice ◽

Eddy Covariance ◽

Co2 Flux ◽

Carbon Dioxide Flux ◽

The Arctic ◽

Closed Path ◽

Eddy Covariance Method ◽

Open Path ◽

Flux Measurements

Abstract. The Arctic marine environment plays an important role in the global carbon cycle. However, there remain large uncertainties in how sea ice affects air–sea fluxes of carbon dioxide (CO2), partially due to disagreement between the two main methods (enclosure and eddy covariance) for measuring CO2 flux (FCO2). The enclosure method has appeared to produce more credible FCO2 than eddy covariance (EC), but is not suited for collecting long-term, ecosystem-scale flux datasets in such remote regions. Here we describe the design and performance of an EC system to measure FCO2 over landfast sea ice that addresses the shortcomings of previous EC systems. The system was installed on a 10 m tower on Qikirtaarjuk Island – a small rock outcrop in Dease Strait located roughly 35 km west of Cambridge Bay, Nunavut, in the Canadian Arctic Archipelago. The system incorporates recent developments in the field of air–sea gas exchange by measuring atmospheric CO2 using a closed-path infrared gas analyzer (IRGA) with a dried sample airstream, thus avoiding the known water vapor issues associated with using open-path IRGAs in low-flux environments. A description of the methods and the results from 4 months of continuous flux measurements from May through August 2017 are presented, highlighting the winter to summer transition from ice cover to open water. We show that the dried, closed-path EC system greatly reduces the magnitude of measured FCO2 compared to simultaneous open-path EC measurements, and for the first time reconciles EC and enclosure flux measurements over sea ice. This novel EC installation is capable of operating year-round on solar and wind power, and therefore promises to deliver new insights into the magnitude of CO2 fluxes and their driving processes through the annual sea ice cycle.

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

10.5194/esd-2018-24 ◽

2018 ◽

Cited By ~ 1

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.

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