Assessment of future heat events for the city of Augsburg by means of a normal vector based analog approach

2020 ◽  
Author(s):  
Christian Merkenschlager ◽  
Christoph Beck ◽  
Elke Hertig
Keyword(s):  
Time Series ◽  
Urban Areas ◽  
General Circulation ◽  
Heat Waves ◽  
Selection Process ◽  
General Circulation Models ◽  
Normal Vector ◽  
Urban Structure ◽  
Data Set ◽  
The City

<p>Under enhanced anthropogenic greenhouse gas forcing heat waves are only one example of climatic risks mankind has to deal with. Especially in urban areas where most of the people will live until the end of the 21<sup>st</sup> century heat waves are a serious risk factor since the urban heat island will reinforce such events. For the city of Augsburg, new analog methods are utilized for assessing the development and impacts of heat waves taking into account the varying urban structure.</p><p>For model calibration the temperature data from the Augsburg-Mühlhausen weather station operated by the German Weather Service (DWD) and atmospheric circulation variables of the ERA5 reanalysis data set were used to analyze the recent temperature development. For this purpose, the least deviation of the normal vector was used to determine a subsample of analogs corresponding to the day of interest. The normal vector was derived from the regression plane of the prevailing circulation on the respective day. Subsequently, the temperature patterns were used to define the analog day from the subsample. For future periods, the same method was applied to model data for two representative concentration pathways (RCP4.5, RCP8.5) of different general circulation models (GCM: ACCESS1-0, CNRM-CM5, MPI-ESM-LR). Thus, we derive future time series of analogs corresponding to events prevailing in the observational period. To account for projected trends of the GCMs, the trends of all time-series were first removed and, after the analog selection process, added again according to the trends of the GCMs.</p><p>Temperature extremes are defined as days with temperatures exceeding the 90<sup>th</sup> quantile (Q90) and heat days are defined as days where at least two temperature indices (TMIN, TMEAN, TMAX) exceed Q90. When at least three consecutive days are defined as heat day a heat wave is proclaimed. Analysis have shown that under consideration of RCP8.5 (RCP4.5) and all model runs the number of heat days in the end of the 21<sup>st</sup> century will be nine (five) times higher than within the reference period 1970-2000. Furthermore, the mean duration of heatwaves will extend by factor four (two), whereby heat waves of more than 30 (15) consecutive days are possible.</p>

scholarly journals Iterative land proxy based reconstruction of SST for the simulation of terrestrial Holocene climate

2012 ◽  
Vol 3 (1) ◽  
pp. 149-200
Author(s):  
K. Haberkorn ◽  
C. Lemmen ◽  
R. Blender ◽  
K. Fraedrich
Keyword(s):  
Time Series ◽  
General Circulation ◽  
Climate Model ◽  
General Circulation Models ◽  
Climate Simulation ◽  
Data Set ◽  
Past Climate ◽  
The North ◽  
Main Driver ◽  
Simulated Climate

Abstract. Sea surface temperature (SST) is the main driver of simulated climate in coupled atmosphere-ocean general circulation models. A reliable reconstruction of past SST is necessary to simulate past climate realistically. We here present a novel method for reconstructing SST on the basis of terrestrial Holocene palaeothermometer data such that a climate model is able to represent the climate mean state in the land temperature time series. For our study, we use the Earth system model of intermediate complexity Planet Simulator (PlaSim). The land climate is represented by the high-resolution and long-term palaeothermometer time series from Lake Ammersee (Southern Germany), where the temperature is derived from the stable δ18O isotope in ostracod valves. To provide a climate simulation which reflects the proxy-derived climate during the Holocene, we (i) determine the sensitivities of the terrestrial PlaSim climate with respect to SST anomalies for present day conditions; (ii) define the inverse of these sensitivities to find the SST conditions necessary for representing past land proxy climate; and (iii) reapply the climate model to this newly reconstructed SST. We iterate over steps (ii) and (iii) until the mean model and proxy climate converge. We demonstrate the applicability of this new method to reconstruct past climate by comparing the simulated land temperatures to an independent (pollen derived) proxy data set of land temperatures for Europe. The implementation of a wider range of terrestrial palaeotemperature information from proxy archives analogous to our method will foreseeably yield better reconstructions of past SST. These can, for example, be used to overcome many models' difficulties with simulations extending to the time before 8500 yr before present, when the North American (Laurentide) ice sheet caused a no-analogue climate.

scholarly journals Assessing local daily temperatures by means of novel analog approaches: a case study based on the city of Augsburg, Germany

2021 ◽  
Author(s):  
Christian Merkenschlager ◽  
Stephanie Koller ◽  
Christoph Beck ◽  
Elke Hertig
Keyword(s):  
Time Series ◽  
Large Scale ◽  
Climate Modeling ◽  
Selection Process ◽  
Urban Climate ◽  
Domain Size ◽  
Normal Vector ◽  
Circulation Patterns ◽  
The City

AbstractWithin the scope of urban climate modeling, weather analogs are used to downscale large-scale reanalysis-based information to station time series. Two novel approaches of weather analogs are introduced which allow a day-by-day comparison with observations within the validation period and which are easily adaptable to future periods for projections. Both methods affect the first level of analogy which is usually based on selection of circulation patterns. First, the time series were bias corrected and detrended before subsamples were determined for each specific day of interest. Subsequently, the normal vector of the standardized regression planes (NVEC) or the center of gravity (COG) of the normalized absolute circulation patterns was used to determine a point within an artificial coordinate system for each day. The day(s) which exhibit(s) the least absolute distance(s) between the artificial points of the day of interest and the days of the subsample is/are used as analog or subsample for the second level of analogy, respectively. Here, the second level of analogy is a second selection process based on the comparison of gridded temperature data between the analog subsample and the day of interest. After the analog selection process, the trends of the observation were added to the analog time series. With respect to air temperature and the exceedance of the 90th temperature quantile, the present study compares the performance of both analog methods with an already existing analog method and a multiple linear regression. Results show that both novel analog approaches can keep up with existing methods. One shortcoming of the methods presented here is that they are limited to local or small regional applications. In contrast, less pre-processing and the small domain size of the circulation patterns lead to low computational costs.

scholarly journals A Time History of Pre- and Post-Bomb Radiocarbon in the Barents Sea Derived from Arcto-Norwegian Cod Otoliths

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 843-855 ◽  
Author(s):  
John M Kalish ◽  
Reidar Nydal ◽  
Kjell H Nedreaas ◽  
George S Burr ◽  
Gro L Eine
Keyword(s):  
Time Series ◽  
Ocean Circulation ◽  
General Circulation ◽  
Barents Sea ◽  
Dissolved Inorganic Carbon ◽  
Time History ◽  
General Circulation Models ◽  
Fine Tuning ◽  
Birth Date ◽  
The Barents Sea

Radiocarbon measured in seawater dissolved inorganic carbon (DIC) can be used to investigate ocean circulation, atmosphere/ocean carbon flux, and provide powerful constraints for the fine-tuning of general circulation models (GCMs). Time series of 14C in seawater are derived most frequently from annual bands of hermatypic corals. However, this proxy is unavailable in temperate and polar oceans. Fish otoliths, calcium carbonate auditory, and gravity receptors in the membranous labyrinths of teleost fishes, can act as proxies for 14C in most oceans and at most depths. Arcto-Norwegian cod otoliths are suited to this application due to the well-defined distribution of this species in the Barents Sea, the ability to determine ages of individual Arcto-Norwegian cod with a high level of accuracy, and the availability of archived otoliths collected for fisheries research over the past 60 years. Using measurements of 14C derived from Arcto-Norwegian cod otoliths, we present the first pre- and post-bomb time series (1919–1992) of 14C from polar seas and consider the significance of these data in relation to ocean circulation and atmosphere/ocean flux of 14C. The data provide evidence for a minor Suess effect of only 0.2‰ per year between 1919 and 1950. Bomb 14C was evident in the Barents Sea as early as 1957 and the highest 14C value was measured in an otolith core from a cod with a birth date of 1967. The otolith 14C data display key features common to records of 14C obtained from a Georges Bank mollusc and corals from the tropical and subtropical North Atlantic.

Urban DAS recording of a vibroseismic campaign with a 21km-long dark fibre in Potsdam, Germany

2021 ◽  
Author(s):  
CharLotte Krawczyk ◽  
Christopher Wollin ◽  
Stefan Lüth ◽  
Martin Lipus ◽  
Christian Cunow ◽  
...  
Keyword(s):  
Urban Areas ◽  
District Heating ◽  
Telecommunication Networks ◽  
Seismic Exploration ◽  
City Centre ◽  
Data Set ◽  
Geothermal Potential ◽  
First Results ◽  
Local Geology ◽  
The City

<p>The de-carbonization strategy of the city of Potsdam, Germany, incorporates the utilization of its geothermal potential.  As a first step of developing a deep geothermal project for district heating, an urban seismic exploration campaign of the Stadtwerke Potsdam took place in December 2020 in the city centre of Potsdam.  Since urban measurements are often difficult to setup and a low-footprint alternative is sought for, we supplemented the contractor-performed Vibroseis survey along three profiles by distributed acoustic sensing (DAS).  In close cooperation with the municipal utilities, we interrogated a 21 km-long dark telecommunication fibre whose trajectory followed the seismic lines as close as possible.  This was accompanied by a network of 15 three-component geophones for further control and research.</p><p>In this contribution we present the data set, the approach for geo-referencing the fibre, and first results regarding DAS recording capabilities of vibroseismic signals in an urban environment.  Following the paradigm that the high density of telecommunication networks in urban areas may facilitate the exploration of the often insufficiently known local geology, we strive to further shed light on the possibilities of their employment for urban exploration.  In this respect we aim at tackling the question of the accuracy of fibre localization, recording sensitivity and range of active stimulation.</p>

scholarly journals Advanced risk-based event attribution for heavy regional rainfall events

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Yukiko Imada ◽  
Hiroaki Kawase ◽  
Masahiro Watanabe ◽  
Miki Arai ◽  
Hideo Shiogama ◽  
...  
Keyword(s):  
General Circulation ◽  
Heavy Rainfall ◽  
Static Pressure ◽  
Heat Waves ◽  
Extreme Temperature ◽  
General Circulation Models ◽  
Rainfall Events ◽  
Pressure Pattern ◽  
Ensemble Simulations ◽  
Event Attribution

Abstract Risk-based event attribution (EA) science involves probabilistically estimating alterations of the likelihoods of particular weather events, such as heat waves and heavy rainfall, owing to global warming, and has been considered as an effective approach with regard to climate change adaptation. However, risk-based EA for heavy rain events remains challenging because, unlike extreme temperature events, which often have a scale of thousands of kilometres, heavy rainfall occurrences depend on mesoscale rainfall systems and regional geographies that cannot be resolved using general circulation models (GCMs) that are currently employed for risk-based EA. Herein, we use GCM large-ensemble simulations and high-resolution downscaled products with a 20-km non-hydrostatic regional climate model (RCM), whose boundary conditions are obtained from all available GCM ensemble simulations, to show that anthropogenic warming increased the risk of two record-breaking regional heavy rainfall events in 2017 and 2018 over western Japan. The events are examined from the perspective of rainfall statistics simulated by the RCM and from the perspective of background large-scale circulation fields simulated by the GCM. In the 2017 case, precipitous terrain and a static pressure pattern in the synoptic field helped reduce uncertainty in the dynamical components, whereas in the 2018 case, a static pressure pattern in the synoptic field provided favourable conditions for event occurrence through a moisture increase under warmer climate. These findings show that successful risk-based EA for regional extreme rainfall relies on the degree to which uncertainty induced by the dynamic components is reduced by background conditioning.

Event detection and visualization of ocean eddies simulated by ocean general circulation model

2019 ◽  
Vol 10 (03) ◽  
pp. 1950018
Author(s):  
Daisuke Matsuoka ◽  
Fumiaki Araki ◽  
Hideharu Sasaki
Keyword(s):  
High Resolution ◽  
General Circulation ◽  
Numerical Study ◽  
Circulation Model ◽  
General Circulation Models ◽  
Ocean Currents ◽  
Time Step ◽  
Data Set ◽  
Ocean Eddies ◽  
Ocean General Circulation

Numerical study of ocean eddies has been carried out by using high-resolution ocean general circulation models. In order to understand ocean eddies from the large volume data produced by simulations, visualizing only eddy distribution at each time step is insufficient; time-variations in eddy events and phenomena must also be considered. However, existing methods cannot precisely find and track eddy events such as amalgamation and bifurcation. In this study, we propose an original approach for eddy detection, tracking, and event visualization based on an eddy classification system. The proposed method detects streams and currents as well as eddies, and it classifies discovered eddies into several categories using the additional stream and current information. By tracking how the classified eddies vary over time, detecting events such as eddy amalgamation and bifurcation as well as the interaction between eddies and ocean currents becomes achievable. We adopt the proposed method for two ocean areas in which strong ocean currents exist as case studies. We visualize the detected eddies and events in a time series of images, allowing us to acquire an intuitive understanding of a region of interest concealed in a high-resolution data set. Furthermore, our proposed method succeeded in clarifying the occurrence place and seasonality of each type of eddy event.

MITIGATION OF TIME SERIES APPROACH ON CLIMATE CHANGE ADAPTATION ON RAINFALL OF WADI AL-AQIQ, MADINAH, SAUDI ARABIA

2017 ◽  
Vol 79 (5) ◽  
Author(s):  
Norhan Abd Rahman ◽  
Zulkifli Yusop ◽  
Zekai Şen ◽  
Saud Taher ◽  
Ibrahim Lawal Kane
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Saudi Arabia ◽  
State Space ◽  
General Circulation ◽  
Temporal Dynamics ◽  
Resource Planning ◽  
General Circulation Models ◽  
Trend Test ◽  
Fluctuation Analysis

Rainfall record plays a significant role in assessment of climate change, water resource planning and management. In arid region, studies on rainfall are rather scarce due to intricacy and constraint of the available data. Most available studies use more advanced approaches such as A2 scenario, General Circulation Models (GCM) and the like, to study the temporal dynamics and make projection on future rainfall. However, those models take no account of the data patterns and its predictability. Therefore, this study uses time series analysis methodologies such as Mann- Kendall trend test, de-trended fluctuation analysis and state space time series approaches to study the dynamics of rainfall records of four stations in and around Wadi Al-Aqiq, Kingdom of Saudi Arabia (KSA). According to Mann-Kendall trend test there are decreasing trend in three out of the four stations. The de-trended fluctuation analysis revealed two distinct scaling properties that spells the predictability of the records and confirmed by state space methods. 

Albedo observations of the Earth’s surface for climate research

1983 ◽  
Vol 309 (1508) ◽  
pp. 285-294 ◽  
Keyword(s):  
General Circulation ◽  
Surface Albedo ◽  
Climate Models ◽  
General Circulation Models ◽  
Data Set ◽  
Primary Input ◽  
Climate Research ◽  
Earth’S Climate ◽  
Atmospheric Distortion ◽  
Spectrally Resolved

The primary input of energy to the Earth’s climate system occurs at the surface and can be highly sensitive to the surface albedo. Albedo changes have been proposed as one cause of climatic variation, but results from climate models are not yet consistent. It is very difficult to establish an agreed global data set with which to initiate comparative climatic simulations. Albedo observations must be spectrally resolved because reflexion of solar radiation is a strong function of wavelength and incident and reflected beams are modified by the atmosphere. Parametrization of system albedos in energybalance models draws on satellite data. The use of satellite observations is less easy in general circulation climate models. The removal of atmospheric distortion is particularly difficult. The establishment of a surface albedo data set generally follows one of two approaches: geographical categorization or remote monitoring. Surface albedo specification in current general circulation models is diverse. This paper reviews the ways in which remotely derived albedo measurements are used now and may, in the future, be improved for climate research.

scholarly journals The dynamics of population distributions in cities based on daily mobile phone operations: A case study of some Moravian cities

2021 ◽  
Vol 29 (1) ◽  
pp. 71-86
Author(s):  
Gabriel Kopáčik ◽  
Antonín Vaishar ◽  
Eva Šimara
Keyword(s):  
Mobile Phone ◽  
Urban Areas ◽  
Urban Structure ◽  
Residential Areas ◽  
Urban Structures ◽  
Population Distributions ◽  
Dynamics Of Population ◽  
The City ◽  
Permanent Residents

Abstract Analyses of the changes in the presence of persons in different central and residential parts of urban areas are subject to evaluation in this paper. Case studies of the cities of Brno, Ostrava and Zlín during the day and night are highlighted. Data from a provider of mobile phone services were used for the analyses. It appears that the data can be important for the comparison of different urban structures. The results demonstrate that the organisation of urban structure affects the number of visitors and thus the area attractiveness. It was confirmed that the number of mobile phone users in the city cores is higher than the number of permanent residents. The greatest differences between the day and night in the city cores were found in Brno, a concentric city with the most important central functions among the cities studied. Differences between the day and night in residential areas were not as large as expected. City neighbourhoods in Brno showed some specific rhythmicity.

Sign in / Sign up

Export Citation Format

Share Document