scholarly journals Spatiotemporal Trends and Attribution of Drought across China from 1901–2100

2020 ◽  
Vol 12 (2) ◽  
pp. 477
Author(s):  
Yongxia Ding ◽  
Shouzhang Peng
Keyword(s):  
Adverse Effects ◽  
General Circulation ◽  
Potential Evapotranspiration ◽  
Northern China ◽  
General Circulation Models ◽  
Research Unit ◽  
Mitigation Strategies ◽  
Climatic Research Unit ◽  
The Past ◽  
Spatiotemporal Trends

Investigating long-term drought trends is of great importance in coping with the adverse effects of global warming. However, little attention has been focused on studying the detailed spatial variability and attribution of drought variation in China. In this study, we first generated a 1 km resolution monthly climate dataset for the period 1901–2100 across China using the delta spatial downscaling method to assess the variability of the Standardized Precipitation Evaporation Index (SPEI). We then developed a simple approach to quantifying the contributions of water supply (precipitation) and demand (potential evapotranspiration, PET) on SPEI variability, according to the meaning of the differentiating SPEI equation. The results indicated that the delta framework could accurately downscale and correct low-spatial-resolution monthly temperatures and precipitation from the Climatic Research Unit and general circulation models (GCMs). Of the 27 GCMs analyzed, the BNU-ESM, CESM1-CAM5, and GFDL-ESM2M were found to be the most accurate in modeling future temperatures and precipitation. We also found that, compared with the past (1901–2017), the climate in the future (2018–2100) will tend toward significant droughts, although both periods showed a high spatial heterogeneity across China. Moreover, the proportion of areas with significantly decreasing SPEI trends was far greater than the proportion of those with increasing trends in most cases, especially for northwestern and northern China. Finally, the proposed approach to quantifying precipitation and PET contributions performed well according to logical evaluations. The percentage contributions of precipitation and PET on SPEI variability varied with study periods, representative concentration pathway scenarios, trend directions, and geographic spaces. In the past, PET contributions for significant downward trends and precipitation contributions for significantly upward trends accounted for 95% and 72%, while their future contributions were 57 ± 22%–149 ± 20% and 95 ± 27%–190 ± 58%, respectively. Overall, our results provide detailed insights for planning flexible adaptation and mitigation strategies to cope with the adverse effects of climate drought across China.

Current and future patterns of forest fire occurrence in China

2020 ◽  
Vol 29 (2) ◽  
pp. 104 ◽  
Author(s):  
Zhiwei Wu ◽  
Hong S. He ◽  
Robert E. Keane ◽  
Zhiliang Zhu ◽  
Yeqiao Wang ◽  
...  
Keyword(s):  
Forest Fire ◽  
General Circulation ◽  
Southern China ◽  
Northern China ◽  
General Circulation Models ◽  
Boosted Regression Trees ◽  
Fire Occurrence ◽  
Representative Concentration Pathways ◽  
Fire Patterns ◽  
In Fire

Forest fire patterns are likely to be altered by climate change. We used boosted regression trees modelling and the MODIS Global Fire Atlas dataset (2003–15) to characterise relative influences of nine natural and human variables on fire patterns across five forest zones in China. The same modelling approach was used to project fire patterns for 2041–60 and 2061–80 based on two general circulation models for two representative concentration pathways scenarios. The results showed that, for the baseline period (2003–15) and across the five forest zones, climate variables explained 37.4–43.5% of the variability in fire occurrence and human activities were responsible for explaining an additional 27.0–36.5% of variability. The fire frequency was highest in the subtropical evergreen broadleaf forests zone in southern China, and lowest in the warm temperate deciduous broadleaved mixed-forests zone in northern China. Projection results showed an increasing trend in fire occurrence probability ranging from 43.3 to 99.9% and 41.4 to 99.3% across forest zones under the two climate models and two representative concentration pathways scenarios relative to the current climate (2003–15). Increased fire occurrence is projected to shift from southern to central-northern China for both 2041–60 and 2061–80.

scholarly journals Streamflow projections for the Brazilian hydropower sector from RCP scenarios

2016 ◽  
Vol 8 (1) ◽  
pp. 114-126 ◽  
Author(s):  
Cleiton da Silva Silveira ◽  
Francisco de Assis de Souza Filho ◽  
Francisco das Chagas Vasconcelos Júnior
Keyword(s):  
Potential Evapotranspiration ◽  
Research Unit ◽  
Climatic Research Unit ◽  
Monthly Precipitation ◽  
Intergovernmental Panel ◽  
Rcp Scenarios ◽  
Soil Moisture Accounting ◽  
Northern Regions ◽  
The Impact ◽  
Observational Record

Streamflow projections were estimated for river basins of relevance to the Brazilian hydroelectric sector from monthly precipitation projections from global models of the fifth report of the Intergovernmental Panel on Climate Change – IPCC-AR5 from 2010 to 2098 for RCP4.5 and RCP8.5 scenarios. Streamflow were computed using the Soil Moisture Accounting Procedure (SMAP) hydrological model, which was forced by bias-corrected precipitation from the monthly rain data of the Climatic Research Unit and by the estimation of potential evapotranspiration according to the Penman–Monteith method. The impacts on average annual streamflow were analyzed for the periods 2010–2039, 2040–2069 and 2070–2098 in comparison with the observational record (historical experiment) from 1950 to 1999. Most IPCC-AR5 models agree in terms of the impact on the electrical sector in the southeastern/midwestern and northern regions, showing that streamflow may be reduced up to 15% in each 30-year period on Furnas basin and approximately 30% by the end of the century in Tucuruí basin under RCP8.5 scenario. In the northeastern sector, the divergence of the models suggests great uncertainty, emphasized in the Xingó basin. In the southern sector, results show increasing streamflow over southernmost Brazil and decreasing over intersection between southern and southeastern regions.

scholarly journals Assessing the climate change adaptation over four European cities

2021 ◽  
Vol 2069 (1) ◽  
pp. 012069
Author(s):  
Yuchen Yang ◽  
Vahid M. Nik
Keyword(s):  
Climate Change ◽  
Thermal Comfort ◽  
Climate Change Adaptation ◽  
General Circulation ◽  
General Circulation Models ◽  
Energy Performance ◽  
Mitigation Strategies ◽  
Climate Scenarios ◽  
European Cities ◽  
Indoor Thermal Comfort

Abstract In recent years, climate change has been widely recognized as a potential problem. The building industry is taking a variety of actions towards sustainable development and climate change mitigation, such as retrofitting buildings. More than mitigation, it is important to account for climate change adaptation and investigate the probable risks and limits for mitigation strategies. For example, one major challenge may become achieving low energy demand without compromising indoor thermal comfort during warm seasons. This work investigates the future energy performance and indoor thermal comfort of four European cities belonging to four different climate zones in Europe; Barcelona, Koln, Brussels, and Copenhagen. An ensemble of future climate scenarios is used, including thirteen climate scenarios considering five different general circulation models (GCM) and three representative concentration pathways (RCP 2.6, RCP 4.5 and RCP 8.5). Through simulating the energy performance of the representative buildings in each city and considering several climate scenarios, this paper provides a comprehensive picture about the energy performance and indoor thermal comfort of the buildings for near-term, medium-term, and long-term climate conditions.

The Advent of Climate Science

2020 ◽  
Author(s):  
Deborah R. Coen
Keyword(s):  
Research Program ◽  
General Circulation ◽  
Modern Science ◽  
Climate Science ◽  
General Circulation Models ◽  
World War ◽  
The Past ◽  
Measurement And Analysis ◽  
History Of ◽  
Definition Of

The advent of climate science can be defined as the historical emergence of a research program to study climate according to a modern definition of climate. Climate in this sense: (1) refers not simply to the average state of the atmosphere but also to its variability; (2) is multiscalar, concerned with phenomena ranging from the very small and fast to the very large and slow; and (3) is understood to be influenced by the oceans, lithosphere, cryosphere, and biosphere. Most accounts of the history of climate science to date have focused on the development of computerized general circulation models since World War Two. However, following this definition, the advent of climate science occurred well before the computer age. This entry therefore seeks to dispel the image of climate science as a recent invention and as the preserve of an exclusive, North American elite. The historical roots of today’s knowledge of climate change stretch surprisingly far back into the past and clear across the world, though the geographic focus here is on Europe and North America. The modern science of climate emerged out of interactions between learned and vernacular knowledge traditions, and has simultaneously appropriated and undermined traditional and indigenous forms of climate knowledge. Important precedents emerged in the 17th and 18th centuries, and it was in the late 19th century that a modern science of climate coalesced into a coordinated research program in part through the unification of divergent knowledge traditions around standardized techniques of measurement and analysis.

Possible pathways to a Dansgaard-Oeschger (DO) PMIP protocol

2021 ◽  
Author(s):  
Irene Malmierca-Vallet ◽  
Louise C. Sime ◽  
Paul J. Valdes
Keyword(s):  
General Circulation ◽  
Climate Changes ◽  
General Circulation Models ◽  
Ice Age ◽  
Climate Change Projections ◽  
The Past ◽  
External Perturbations ◽  
Mis 3 ◽  
Last Ice Age ◽  
Earth System Models

<p>The DO events of the last ice age represent one of the best studied abrupt climate transitions, yet we still lack a comprehensive explanation for them. There is uncertainty whether current IPCC-relevant models can effectively represent the processes that cause DO events. Current Earth system models (ESMs) seem overly stable against external perturbations and incapable of reproducing most abrupt climate changes of the past (Valdes, 2011). If this holds true, this could noticeably influence their capability to predict future abrupt transitions, with significant consequences for the delivery of precise climate change projections.  In this task, the objectives of this study are (1) to cross compare existing simulations that show spontaneous DO-type oscillations using a common set of diagnostics so we can compare the mechanisms and the characteristics of the oscillations, and (2) to formulate possible pathways to a DO PMIP protocol that could help investigate cold-period instabilities through a range of insolation-, freshwater-, GHG-, and NH ice sheet-related forcings, as well as evaluating the possibility of spontaneous internal oscillations.</p><p>Although most abrupt DO events happened during MIS3, only few studies investigate DO events in coupled general circulation models under MIS 3 conditions (e.g., Kawamura et al., 2017; Zhang and Prange, 2020). Here, we thus propose that the MIS3 period could be the focus of such a DO-event modelling protocol. More specific sensitivity experiments performed under MIS 3 boundary conditions are needed in order to (1) better understand the mechanisms behind millennial-scale climate variability, (2) explore AMOC variability under intermediate glacial conditions, and (3) help answer the question: “are models too stable?”.</p>

Assessing the relation of tree ring width with climate variables in South Korea through multi-gridded dataset

2021 ◽  
Author(s):  
Nasrin Salehnia ◽  
Jinho Ahn
Keyword(s):  
Tree Ring ◽  
Potential Evapotranspiration ◽  
Regression Line ◽  
Ring Width ◽  
Climatic Research Unit ◽  
P Value ◽  
Climate Variables ◽  
Tree Ring Width ◽  
Significance Level ◽  
The Past

<p>The Tree Ring Width (TRW) records are one of the main paleoclimate proxies that estimate the past climate variability. TRW measurements pave the way for scientists to produce sequences from various kinds of trees and reconstruct climate variables over the past years. Understanding the relation between TRW and climate variables in the past would help us analyze climate change events. This study has applied multi-gridded datasets to find the relations and model TRW data with different climate variables in South Korea's northeast. We utilized TRW data related to our case study that is available on the NOAA website; furthermore, we have checked three primary gauges, namely Agmerra (The Modern-Era Retrospective Analysis for Research and Applications), CRU TS4.03 (Climatic Research Unit Time-Series version 4.03), and APHRODITE's (Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation) for climate variables. In the first step, we have checked the relation between the gauges' precipitation data and observation TRW. According to the obtained efficiency criteria, CRU performed the best consequences. In the second step, we have tried to model observation TRW as a dependent variable and four climate variables of CRU (precipitation, minimum temperature, potential evapotranspiration, and diurnal temperature range) as independent ones over 1969-1998. We have created a linear regression model and determined the accurate coefficients for each climate variable. Besides, we have examined the observation TRW and modeled TRW data. The results showed that with <em>R<sup>2 </sup></em><sup> </sup>≈ 0.40 and a <em>p-value</em> of 0.0323, the regression line was linearly significant at the 95 percent significance level. It represents that our model is acceptable. We will extend our model with Artificial Intelligence methods and try to apply other TRW stations in the future step. In this way, we may produce highly accurate models and fill the gaps for future researches.</p>

scholarly journals A climate model intercomparison for the Antarctic region: present and past

2012 ◽  
Vol 8 (2) ◽  
pp. 803-814 ◽  
Author(s):  
M. N. A. Maris ◽  
B. de Boer ◽  
J. Oerlemans
Keyword(s):  
General Circulation ◽  
Climate Model ◽  
Reference Data ◽  
Regional Climate ◽  
Ice Core ◽  
Ice Sheet ◽  
General Circulation Models ◽  
Antarctic Region ◽  
The Past ◽  
The Antarctic

Abstract. Eighteen General Circulation Models (GCMs) are compared to reference data for the present, the Mid-Holocene (MH) and the Last Glacial Maximum (LGM) for the Antarctic region. The climatology produced by a regional climate model is taken as a reference climate for the present. GCM results for the past are compared to ice-core data. The goal of this study is to find the best GCM that can be used to drive an ice sheet model that simulates the evolution of the Antarctic Ice Sheet. Because temperature and precipitation are the most important climate variables when modelling the evolution of an ice sheet, these two variables are considered in this paper. This is done by ranking the models according to how well their output corresponds with the references. In general, present-day temperature is simulated well, but precipitation is overestimated compared to the reference data. Another finding is that model biases play an important role in simulating the past, as they are often larger than the change in temperature or precipitation between the past and the present. Considering the results for the present-day as well as for the MH and the LGM, the best performing models are HadCM3 and MIROC 3.2.2.

scholarly journals Influence of Tropical Tropopause Layer Cooling on Atlantic Hurricane Activity

2013 ◽  
Vol 26 (7) ◽  
pp. 2288-2301 ◽  
Author(s):  
Kerry Emanuel ◽  
Susan Solomon ◽  
Doris Folini ◽  
Sean Davis ◽  
Chiara Cagnazzo
Keyword(s):  
Tropical Cyclone ◽  
General Circulation ◽  
General Circulation Models ◽  
Tropical Cyclone Activity ◽  
Sea Surface ◽  
Cyclone Activity ◽  
Tropical Tropopause Layer ◽  
The Past ◽  
Tropical Tropopause ◽  
Atlantic Tropical Cyclone

Abstract Virtually all metrics of Atlantic tropical cyclone activity show substantial increases over the past two decades. It is argued here that cooling near the tropical tropopause and the associated decrease in tropical cyclone outflow temperature contributed to the observed increase in tropical cyclone potential intensity over this period. Quantitative uncertainties in the magnitude of the cooling are important, but a broad range of observations supports some cooling. Downscalings of the output of atmospheric general circulation models (AGCMs) that are driven by observed sea surface temperatures and sea ice cover produce little if any increase in Atlantic tropical cyclone metrics over the past two decades, even though observed variability before roughly 1970 is well simulated by some of the models. Part of this shortcoming is traced to the failure of the AGCMs examined to reproduce the observed cooling of the lower stratosphere and tropical tropopause layer (TTL) over the past few decades. The authors caution against using sea surface temperature or proxies based on it to make projections of tropical cyclone activity as there can be significant contributions from other variables such as the outflow temperature. The proposed mechanisms of TTL cooling (e.g., ozone depletion and stratospheric circulation changes) are reviewed, and the need for improved representations of these processes in global models in order to improve projections of future tropical cyclone activity is emphasized.

scholarly journals Projection of Water Availability and Sustainability in Nigeria Due to Climate Change

2021 ◽  
Vol 13 (11) ◽  
pp. 6284
Author(s):  
Mohammed Sanusi Shiru ◽  
Shamsuddin Shahid ◽  
Inhwan Park
Keyword(s):  
Climate Change ◽  
Water Availability ◽  
General Circulation ◽  
Water Storage ◽  
Coupled Model ◽  
General Circulation Models ◽  
Research Unit ◽  
Wet Season ◽  
Spatiotemporal Changes ◽  
Terrestrial Water

This study projects water availability and sustainability in Nigeria due to climate change. This study used Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage data (TWS), Global Precipitation Climatology Center (GPCC) precipitation data and Climate Research Unit (CRU) temperature data. Four general circulation models (GCMs) of the Coupled Model Intercomparison Project 5 were downscaled using the best of four downscaling methods. Two machine learning (ML) models, RF and SVM, were developed to simulate GRACE TWS data for the period 2002–2016 and were then used for the projection of spatiotemporal changes in TWS. The projected TWS data were used to assess the spatiotemporal changes in water availability and sustainability based on the reliability–resiliency–vulnerability (RRV) concept. This study revealed that linear scaling was the best for downscaling over Nigeria. RF had better performance than SVM in modeling TWS for the study area. This study also revealed there would be decreases in water storage during the wet season (June–September) and increases in the dry season (January–May). Decreases in projected water availability were in the range of 0–12 mm for the periods 2010–2039, 2040–2069, and 2070–2099 under RCP2.6 and in the range of 0–17 mm under RCP8.5 during the wet season. Spatially, annual changes in water storage are expected to increase in the northern part and decrease in the south, particularly in the country’s southeast. Groundwater sustainability was higher during the period 2070–2099 under all RCPs compared to the other periods and this can be attributed to the expected increases in rainfall during this period.

Sign in / Sign up

Export Citation Format

Share Document