scholarly journals A Transient Stochastic Rainfall Generator for Climate Changes Analysis at Hydrological Scales in Central Italy

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1292
Author(s):  
Davide Luciano De Luca ◽  
Andrea Petroselli ◽  
Luciano Galasso
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Climate Changes ◽  
Probability Distributions ◽  
Central Italy ◽  
Kendall Test ◽  
Rain Gauge ◽  
Rainfall Series ◽  
Rainfall Time Series ◽  
Climate Change Effects

In this work, a comprehensive methodology for trend investigation in rainfall time series, in a climate-change context, is proposed. The crucial role played by a Stochastic Rainfall Generator (SRG) is highlighted. Indeed, SRG application is particularly suitable to obtain rainfall series that are representative of future rainfall series at hydrological scales. Moreover, the methodology investigates the climate change effects on several timescales, considering the well-known Mann–Kendall test and analyzing the variation of probability distributions of extremes and hazard. The hypothesis is that the effects of climate changes could be more evident only for specific time resolutions, and only for some considered aspects. Applications regarded the rainfall time series of the Viterbo rain gauge in Central Italy.

scholarly journals Analysis of Climate Change Effects on Surface Temperature in Central-Italy Lakes Using Satellite Data Time-Series

2021 ◽  
Vol 14 (1) ◽  
pp. 117
Author(s):  
Davide De Santis ◽  
Fabio Del Frate ◽  
Giovanni Schiavon
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Surface Temperature ◽  
Satellite Data ◽  
Water Surface ◽  
Central Italy ◽  
Large Lakes ◽  
Climate Change Effects ◽  
Surface Temperatures ◽  
The Impact

Evaluation of the impact of climate change on water bodies has been one of the most discussed open issues of recent years. The exploitation of satellite data for the monitoring of water surface temperatures, combined with ground measurements where available, has already been shown in several previous studies, but these studies mainly focused on large lakes around the world. In this work the water surface temperature characterization during the last few decades of two small–medium Italian lakes, Lake Bracciano and Lake Martignano, using satellite data is addressed. The study also takes advantage of the last space-borne platforms, such as Sentinel-3. Long time series of clear sky conditions and atmospherically calibrated (using a simplified Planck’s Law-based algorithm) images were processed in order to derive the lakes surface temperature trends from 1984 to 2019. The results show an overall increase in water surface temperatures which is more evident on the smallest and shallowest of the two test sites. In particular, it was observed that, since the year 2000, the surface temperature of both lakes has risen by about 0.106 °C/year on average, which doubles the rate that can be retrieved by considering the whole period 1984–2019 (0.053 °C/year on average).

Modeling climate change impacts on combined sewer overflow using synthetic precipitation time series

2013 ◽  
Vol 68 (1) ◽  
pp. 160-166 ◽  
Author(s):  
David Bendel ◽  
Ferdinand Beck ◽  
Ulrich Dittmer
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Climate Change Impacts ◽  
Rainfall Time Series ◽  
Combined Sewer Overflows ◽  
Precipitation Time Series ◽  
Climate Change Effects ◽  
Combined Sewer ◽  
Synthetic Precipitation

In the presented study climate change impacts on combined sewer overflows (CSOs) in Baden-Wuerttemberg, Southern Germany, were assessed based on continuous long-term rainfall–runoff simulations. As input data, synthetic rainfall time series were used. The applied precipitation generator NiedSim-Klima accounts for climate change effects on precipitation patterns. Time series for the past (1961–1990) and future (2041–2050) were generated for various locations. Comparing the simulated CSO activity of both periods we observe significantly higher overflow frequencies for the future. Changes in overflow volume and overflow duration depend on the type of overflow structure. Both values will increase at simple CSO structures that merely divide the flow, whereas they will decrease when the CSO structure is combined with a storage tank. However, there is a wide variation between the results of different precipitation time series (representative for different locations).

scholarly journals Mediterranean Sea climatic indices: monitoring long term variability and climate changes

2018 ◽  
Author(s):  
Athanasia Iona ◽  
Athanasios Theodorou ◽  
Sarantis Sofianos ◽  
Sylvain Watelet ◽  
Charles Troupin ◽  
...  
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Mediterranean Sea ◽  
Climate Changes ◽  
Salt Content ◽  
Climatic Indices ◽  
In Situ Observations ◽  
The Mediterranean

Abstract. We present a new product composed of a set of thermohaline climatic indices from 1950 to 2015 for the Mediterranean Sea such as decadal temperature and salinity anomalies, their mean values over selected depths, decadal ocean heat and salt content anomalies at selected depth layers as well as their long times series. It is produced from a new high-resolution climatology of temperature and salinity on a 1/8° regular grid based on historical high quality in situ observations. Ocean heat and salt content differences between 1980–2015 and 1950–1979 are compared for evaluation of the climate shift in the Mediterranean Sea. The spatial patterns of heat and salt content shifts demonstrate in greater detail than ever before that the climate changes differently in the several regions of the basin. Long time series of heat and salt content for the period 1950 to 2015 are also provided which indicate that in the Mediterranean Sea there is a net mean volume warming and salting since 1950 with acceleration during the last two decades. The time series also show that the ocean heat content seems to fluctuate on a cycle of about 40 years and seems to follow the Atlantic Multidecadal Oscillation climate cycle indicating that the natural large scale atmospheric variability could be superimposed on to the warming trend. This product is an observations-based estimation of the Mediterranean climatic indices. It relies solely on spatially interpolated data produced from in-situ observations averaged over decades in order to smooth the decadal variability and reveal the long term trends with more accuracy. It can provide a valuable contribution to the modellers' community, next to the satellite-based products and serve as a baseline for the evaluation of climate-change model simulations contributing thus to a better understanding of the complex response of the Mediterranean Sea to the ongoing global climate change. The product is available here: https://doi.org/10.5281/zenodo.1210100.

scholarly journals Tropical rainfall trend and stationarity analysis

2020 ◽  
Vol 20 (7) ◽  
pp. 2471-2483
Author(s):  
Chun Kang Ng ◽  
Jing Lin Ng ◽  
Yuk Feng Huang ◽  
Yi Xun Tan ◽  
Majid Mirzaei
Keyword(s):  
Climate Change ◽  
Trend Analysis ◽  
River Basin ◽  
Spatial Scales ◽  
Kendall Test ◽  
Temporal Analysis ◽  
Northern Region ◽  
Rainfall Series ◽  
Kelantan River Basin ◽  
Temporal And Spatial

Abstract Climate change is most likely to cause changes to the temporal and spatial variability of rainfall. A trend analysis to investigate the rainfall pattern can detect changes over temporal and spatial scales for a rainfall series. In this study, trend analysis using the Mann–Kendall test and Sen's slope estimator was conducted in the Kelantan River Basin, Malaysia. The Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test was applied to evaluate the stationarity of the rainfall series. This basin annually faces onslaughts of varying year-end flooding conditions. The trend analysis was applied for monthly, seasonal and yearly rainfall series between 1989 and 2018. The temporal analysis results showed that both increasing and decreasing trends were detected for all rainfall series. The spatial analysis results indicated that the northern region of the Kelantan River Basin showed an increasing trend, whilst the southwest region showed a decreasing trend. It was found that almost all the rainfall series were stationary except at two rainfall stations during the Inter Monsoon 1, Inter Monsoon 2 and yearly rainfall series. Results obtained from this study can be used as reference for water resources planning and climate change assessment.

scholarly journals To what extent does variability of historical rainfall series influence extreme event statistics of sewer system surcharge and overflows?

2009 ◽  
Vol 60 (1) ◽  
pp. 87-95 ◽  
Author(s):  
K. Schaarup-Jensen ◽  
M. R. Rasmussen ◽  
S. Thorndahl
Keyword(s):  
Extreme Events ◽  
Extreme Event ◽  
Rain Gauge ◽  
Water Levels ◽  
Rainfall Series ◽  
Rainfall Time Series ◽  
Extreme Statistics ◽  
Maximum Water ◽  
Present Case Study

In urban drainage modelling long term extreme statistics has become an important basis for decision-making e.g. in connection with renovation projects. Therefore it is of great importance to minimize the uncertainties with regards to long term prediction of maximum water levels and combined sewer overflow (CSO) in drainage systems. These uncertainties originate from large uncertainties regarding rainfall inputs, parameters, and assessment of return periods. This paper investigates how the choice of rainfall time series influences the extreme events statistics of max water levels in manholes and CSO volumes. Traditionally, long term rainfall series, from a local rain gauge, are unavailable. In the present case study, however, long and local rain series are available. 2 rainfall gauges have recorded events for approximately 9 years at 2 locations within the catchment. Beside these 2 gauges another 7 gauges are located at a distance of max 20 kilometers from the catchment. All gauges are included in the Danish national rain gauge system which was launched in 1976. The paper describes to what extent the extreme events statistics based on these 9 series diverge from each other and how this diversity can be handled, e.g. by introducing an “averaging procedure” based on the variability within the set of statistics. All simulations are performed by means of the MOUSE LTS model.

scholarly journals Evaluating the climate change effects on temperature, precipitation and evapotranspiration in eastern Iran using CMPI5

2021 ◽  
Author(s):  
Guangli Fan ◽  
Amjad Sarabandi ◽  
Mostafa Yaghoobzadeh
Keyword(s):  
Climate Change ◽  
Climate Changes ◽  
Maximum Temperature ◽  
Emission Scenarios ◽  
Future Period ◽  
Climate Change Effects ◽  
Eastern Iran ◽  
Large Fluctuations ◽  
Rcp 8.5 ◽  
Maximum Temperatures

Abstract In this study, the trend of climate changes during a future period from 2020 to 2039 has been evaluated using the data of the Fifth Climate Change Report under two emission scenarios RCP 4.5 and RCP 8.5 for Neishabour plain, Iran. Eleven models such as CESM, EC EARTH, HADGEM, MPI, NORESM, CANESM, CSIROM, GFDLCM2, GISS E2, IPSL and MIROC ESM have been used to evaluate changes in minimum and maximum temperatures, precipitation, and evapotranspiration. The results showed that GFDLCM2, MPI and IPSL models were more accurate in terms of precipitation and GISS E2 and GFDLCM2 models were the suitable option for predicting the maximum and minimum temperatures and evapotranspiration. Considering the evaluated parameters, minimum temperature, maximum temperature and evapotranspiration had approximately the constant trends and were accompanied by a slight increase and decrease for the next two decades, but for the precipitation, large fluctuations were predicted for the next period. Moreover, in the study years for the four parameters in all simulated models, the RCP 8.5 scenario has estimated a higher amount than the RCP 4.5 scenario.

scholarly journals Energy Efficiency Policies to Face Buildings’ Climate Change Effects in Paraguay

2020 ◽  
Vol 10 (11) ◽  
pp. 3979
Author(s):  
Fabiana Silvero ◽  
Fernanda Rodrigues ◽  
Sergio Montelpare
Keyword(s):  
Climate Change ◽  
Energy Efficiency ◽  
Climate Changes ◽  
South American ◽  
Building Sector ◽  
Hydroelectric Energy ◽  
Climate Change Effects ◽  
Energy Demands ◽  
Mitigate Climate Change ◽  
Energy Efficiency Policies

Nowadays, the importance of implementing energy efficiency (EE) measures is growing significantly worldwide, based on its potential to reduce energy demands and mitigate climate change effects. Paraguay is a developing country with the highest per capita hydroelectric energy generation in the world, but only 18% of local consumption is hydroelectric and 41% of its energy matrix corresponds to oil products. This paper aims to analyse the importance the Country places on EE as a strategy towards sustainable development and to highlight as EE is an effective pathway to mitigate the climate changes and contrast their effects. The authors initially provide an insight into the climate scenarios for Paraguay and underline the effects of the climate changes on the buildings’ comfort. Subsequently, the authors provide, by resourcing a bibliographic review, a description of the Paraguayan sectors of greater energy consumption, its policies and targets set for increasing EE. Besides, the main EE projects developed by other neighbouring South American countries are analysed to show the level of development of each one in the scope of EE and to offer a reference basis of potential virtuous solutions to be adopted in Paraguay. A focus on the building sector is also made to provide a foundation for policy analyses to enhance EE in this sector. As a result of this review, evidence that EE is beginning to take part in Paraguay’s public policies was found, with the leaders becoming aware of its importance. Nevertheless, many concrete results could not be achieved as of yet and overcoming these barriers still involve a great challenge. Regarding the building sector, few advances have been noticed regarding the regulations of buildings’ thermal performance, a reason for which the National objectives set need to be more specific to achieve greater collective awareness to enforce them. Finally, key actions are recommended for Paraguay aiming to improve EE levels to face the climate change phenomenon.

Climate change effects on forest floor interception in woody Cerrado ecosystem

2021 ◽  
Author(s):  
Livia Rosalem ◽  
Miriam Gerrits-Coenders ◽  
Jamil A. A. Anache ◽  
Julian S. Sone ◽  
Dimaghi Schwamback ◽  
...  
Keyword(s):  
Climate Change ◽  
Forest Floor ◽  
Climate Changes ◽  
Climate Model ◽  
Regional Climate ◽  
Climate Change Scenarios ◽  
Water Fluxes ◽  
Climate Change Effects ◽  
Water Partitioning ◽  
Evaporative Flux

<p>The interception process is an important redistributor of water fluxes, which can considerably affect terrestrial evaporation. Not only the canopy intercepts water, but also from the forest floor significant amounts of water vapor return to the atmosphere. Remaining forests are important areas to evaluate the possible effects of climate change on the water partitioning process. Despite the hydrologic and ecosystem services offered by Cerrado forests, the interception process, as well as climate change threats on the evaporative flux of such forests, are still unknown. This study attempts to anticipate the possible impacts on the forest floor interception process in Cerrado stricto sensu considering future scenarios of climate change. To accomplish this, we used data of field monitoring from June 2017 to February 2020 in an undisturbed Cerrado s.s. forest in São Paulo State, Brazil. We calibrated and validated an improved version of the Rutter interception model (Rutter et al., 1971), which includes interception from the forest floor. Projected climate change scenarios were obtained from the National Institute for Space Research (INPE, Brazil) from 2006 to 2099 with 5km spatial resolution generated by Eta-HadGEM2-ES regional climate model under representative concentration pathway (RCP) 4.5. The results indicate increased rainfall and decreased potential evaporation in the decade 2041-2060. By the Rutter model, the total interception increased for this period (2041-2060) associated with decreased forest floor evaporation. During the first (2006-2020) and the last (2081-2099) decades, the predictions suggest an increase of 2.4% on the average annual percentage of forest floor evaporation, also an increase of minimum annual interception percentages (from 17.1% to 18.7%). Thus, our results demonstrate the relevance of forest floor to the interception process and suggest that it can be even more relevant in the future due to the climate changes.</p>

Hybrid of ARIMA-GARCH Modeling in Rainfall Time Series

2013 ◽  
Vol 63 (2) ◽  
Author(s):  
Fadhilah Yusof ◽  
Ibrahim Lawal Kane ◽  
Zulkifli Yusop
Keyword(s):  
Time Series ◽  
Daily Rainfall ◽  
Rainfall Series ◽  
Empirical Modeling ◽  
Dependence Structure ◽  
Rainfall Time Series ◽  
Arima Models ◽  
Starting Point ◽  
Garch Modeling ◽  
Squared Residuals

The dependence structure of rainfall is usually very complex both in time and space. It is shown in this paper that the daily rainfall series of Ipoh and Alorsetar are affected by nonlinear characteristics of the variance often referred to as variance clustering or volatility, where large changes tend to follow large changes and small changes tend to follow small changes. In most empirical modeling of hydrological time series, the focus was on modeling and predicting the mean behavior of the time series through conventional methods of an Autoregressive Moving Average (ARMA) modeling proposed by the Box Jenkins methodology. The conventional models operate under the assumption that the series is stationary that is: constant mean and either constant variance or season-dependent variances, however, does not take into account the second order moment or conditional variance, but they form a good starting point for time series analysis. The residuals from preliminary ARIMA models derived from the daily rainfall time series were tested for ARCH behavior. The autocorrelation structure of the residuals and the squared residuals were inspected, the residuals are uncorrelated but the squared residuals show autocorrelation, the Ljung-Box test confirmed the results. McLeod-Li test and a test based on the Lagrange multiplier (LM) principle were applied to the squared residuals from ARIMA models. The results of these auxiliary tests show clear evidence to reject the null hypothesis of no ARCH effect. Hence indicates that GARCH modeling is necessary. Therefore the composite ARIMA-GARCH model captures the dynamics of the daily rainfall series in study areas more precisely. On the other hand, Seasonal ARIMA model became a suitable model for the monthly average rainfall series of the same locations treated.

Impacts of global climate change in a hydrologically vulnerable region: challenges to South African hydrologists

1997 ◽  
Vol 21 (1) ◽  
pp. 113-136 ◽  
Author(s):  
R.E. Schulze
Keyword(s):  
Climate Change ◽  
South Africa ◽  
South African ◽  
Southern Africa ◽  
Climate Changes ◽  
Global Climate ◽  
Sensitivity Study ◽  
Hydrological Models ◽  
Climate Change Effects

South Africa is already hydrologically vulnerable and this is likely to be exacerbated by both nonpermanent ENSO-related as well as more permanently greenhouse-gas forced climate changes. Climate change effects are explained by way of the hydrological equation. This serves as a backdrop to a brief review, in a hydrological context, of projected perturbations to temperature, rainfall and potential evaporation, over southern Africa. Methodologies for simulating hydro logical responses to climate change are assessed. These include more direct GCM-derived output, with some emphasis on recent advances in climatic downscaling, and the application of appro priate hydrological models for use in impact studies. Scale problems of importance to hydrologists are highlighted. Directions to which climate change-related hydrological research efforts should be expended in South Africa are summarized, before two case study simulations, one a general sensitivity study of hydrological responses to changes in rainfall over southern Africa, the other a more specific hydrological response study to the El Niño of the 1982-83 season, are presented. The article concludes with a discussion on whether or not water resources practitioners in South Africa should respond to climate change.

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