scholarly journals Global precipitation response to changing external forcings since 1870

2011 ◽  
Vol 11 (3) ◽  
pp. 9375-9405
Author(s):  
A. Bichet ◽  
M. Wild ◽  
D. Folini ◽  
C. Schär
Keyword(s):  
Climate Model ◽  
Decadal Variability ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Global Climate Model ◽  
Temperature And Precipitation ◽  
Global Land ◽  
Climate Forcings ◽  
Aerosol Emissions ◽  
Global Precipitation

Abstract. Predicting and adapting to changes in the hydrological cycle is one of the major challenges for the twenty-first century. To better estimate how it will respond to future changes in climate forcings, it is crucial to understand how it has evolved in the past and why. In our study, we use an atmospheric global climate model with prescribed sea surface temperatures (SSTs) to investigate how changing external climate forcings have affected global land temperature and precipitation in the period 1870–2005. We show that prescribed SSTs (encapsulating other forcings) are the dominant forcing driving the decadal variability of land temperature and precipitation since 1870. On top of this SSTs forcing, we also find that the atmosphere-only response to increasing aerosol emissions is a reduction in global land temperature and precipitation by up to 0.4 °C and 30 mm year−1, respectively, between about 1930 and 2000. Similarly, the atmosphere-only response to increasing greenhouse gas concentrations is an increase in global land temperature and precipitation by up to 0.25 °C and 10 mm year−1, respectively, between about 1950 and 2000. Finally, our results also suggest that between about 1950 and 1970, increasing aerosol emissions had a larger impact on the hydrological cycle than increasing greenhouse gases concentrations.

scholarly journals Global precipitation response to changing forcings since 1870

2011 ◽  
Vol 11 (18) ◽  
pp. 9961-9970 ◽  
Author(s):  
A. Bichet ◽  
M. Wild ◽  
D. Folini ◽  
C. Schär
Keyword(s):  
Greenhouse Gas ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Global Climate Model ◽  
Internal Variability ◽  
Temperature And Precipitation ◽  
Global Land ◽  
Climate Forcings ◽  
Aerosol Emissions

Abstract. Predicting and adapting to changes in the hydrological cycle is one of the major challenges for the 21st century. To better estimate how it will respond to future changes in climate forcings, it is crucial to understand how the hydrological cycle has evolved in the past and why. In our study, we use an atmospheric global climate model with prescribed sea surface temperatures (SSTs) to investigate how, in the period 1870–2005, changing climate forcings have affected the global land temperature and precipitation. We show that between 1870 and 2005, prescribed SSTs (encapsulating other forcings and internal variability) determine the decadal and interannual variabilities of the global land temperature and precipitation, mostly via their influence in the tropics (25° S–25° N). In addition, using simulations with prescribed SSTs and considering the atmospheric response alone, we find that between 1930 and 2005 increasing aerosol emissions have reduced the global land temperature and precipitation by up to 0.4 °C and 30 mm yr−1, respectively, and that between about 1950 and 2005 increasing greenhouse gas concentrations have increased them by up to 0.25 °C and 10 mm yr−1, respectively. Finally, we suggest that between about 1950 and 1970, increasing aerosol emissions had a larger impact on the hydrological cycle than increasing greenhouse gas concentrations.

scholarly journals Global change in flood and drought intensities under climate change in the 21<sup>st</sup> century

2017 ◽  
Author(s):  
Behzad Asadieh ◽  
Nir Y. Krakauer
Keyword(s):  
21St Century ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Global Climate Model ◽  
The Arctic ◽  
Simultaneous Increase ◽  
Drought Intensity ◽  
Global Land ◽  
Streamflow Extremes

Abstract. Global warming is expected to intensify the Earth’s hydrological cycle and increase flood and drought risks. Changes in global high and low streamflow extremes over the 21st century under two warming scenarios are analyzed as indicators of hydrologic flood and drought intensity, using an ensemble of bias-corrected global climate model (GCM) fields fed into different global hydrological models (GHMs). Based on multi-model mean, approximately 37 % and 43 % of global land areas are exposed to increases in flood and drought intensities, respectively, by the end of the 21st century under RCP8.5 scenario. The average rates of increase in flood and drought intensities in those areas are projected to be 24.5 % and 51.5 %, respectively. Nearly 10 % of the global land areas are under the potential risk of simultaneous increase in both flood and drought intensities, with average rates of 10.1 % and 19.8 %, respectively; further, these regions tend to be highly populated parts of the globe, currently holding around 30 % of the world’s population (over 2.1 billion people). In a world more than 4 degrees warmer by the end of the 21st century compared to the pre-industrial era (RCP8.5 scenario), increases in flood and drought intensities are projected to be nearly twice as large as in a 2 degree warmer world (RCP2.6 scenario). Results also show that GHMs contribute to more uncertainties in streamflow changes than the GCMs. Under both forcing scenarios, there is high model agreement for significant increases in streamflow of the regions near and above the Arctic Circle, and consequent increases in the freshwater inflow to the Arctic Ocean, while subtropical arid areas experience reduction in streamflow.

scholarly journals Global change in streamflow extremes under climate change over the 21st century

2017 ◽  
Vol 21 (11) ◽  
pp. 5863-5874 ◽  
Author(s):  
Behzad Asadieh ◽  
Nir Y. Krakauer
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Global Climate Model ◽  
The Arctic ◽  
Average Decrease ◽  
Global Land ◽  
Streamflow Extremes

Abstract. Global warming is expected to intensify the Earth's hydrological cycle and increase flood and drought risks. Changes over the 21st century under two warming scenarios in different percentiles of the probability distribution of streamflow, and particularly of high and low streamflow extremes (95th and 5th percentiles), are analyzed using an ensemble of bias-corrected global climate model (GCM) fields fed into different global hydrological models (GHMs) provided by the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) to understand the changes in streamflow distribution and simultaneous vulnerability to different types of hydrological risk in different regions. In the multi-model mean under the Representative Concentration Pathway 8.5 (RCP8.5) scenario, 37 % of global land areas experience an increase in magnitude of extremely high streamflow (with an average increase of 24.5 %), potentially increasing the chance of flooding in those regions. On the other hand, 43 % of global land areas show a decrease in the magnitude of extremely low streamflow (average decrease of 51.5 %), potentially increasing the chance of drought in those regions. About 10 % of the global land area is projected to face simultaneously increasing high extreme streamflow and decreasing low extreme streamflow, reflecting the potentially worsening hazard of both flood and drought; further, these regions tend to be highly populated parts of the globe, currently holding around 30 % of the world's population (over 2.1 billion people). In a world more than 4° warmer by the end of the 21st century compared to the pre-industrial era (RCP8.5 scenario), changes in magnitude of streamflow extremes are projected to be about twice as large as in a 2° warmer world (RCP2.6 scenario). Results also show that inter-GHM uncertainty in streamflow changes, due to representation of terrestrial hydrology, is greater than the inter-GCM uncertainty due to simulation of climate change. Under both forcing scenarios, there is high model agreement for increases in streamflow of the regions near and above the Arctic Circle, and consequent increases in the freshwater inflow to the Arctic Ocean, while subtropical arid areas experience a reduction in streamflow.

scholarly journals A Mathematical Framework for Analysis of Water Tracers. Part II: Understanding Large-Scale Perturbations in the Hydrological Cycle due to CO2 Doubling

2016 ◽  
Vol 29 (18) ◽  
pp. 6765-6782 ◽  
Author(s):  
Hansi K. A. Singh ◽  
Cecilia M. Bitz ◽  
Aaron Donohoe ◽  
Jesse Nusbaumer ◽  
David C. Noone
Keyword(s):  
Moisture Transport ◽  
Large Scale ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Global Climate Model ◽  
Mathematical Framework ◽  
Surface Evaporation ◽  
And Shifts

Abstract The aerial hydrological cycle response to CO2 doubling from a Lagrangian, rather than Eulerian, perspective is evaluated using information from numerical water tracers implemented in a global climate model. While increased surface evaporation (both local and remote) increases precipitation globally, changes in transport are necessary to create a spatial pattern where precipitation decreases in the subtropics and increases substantially at the equator. Overall, changes in the convergence of remotely evaporated moisture are more important to the overall precipitation change than changes in the amount of locally evaporated moisture that precipitates in situ. It is found that CO2 doubling increases the fraction of locally evaporated moisture that is exported, enhances moisture exchange between ocean basins, and shifts moisture convergence within a given basin toward greater distances between moisture source (evaporation) and sink (precipitation) regions. These changes can be understood in terms of the increased residence time of water in the atmosphere with CO2 doubling, which corresponds to an increase in the advective length scale of moisture transport. As a result, the distance between where moisture evaporates and where it precipitates increases. Analyses of several heuristic models further support this finding.

scholarly journals Glacier dynamics in the Western Italian Alps: a minimal model approach

2014 ◽  
Vol 8 (2) ◽  
pp. 1479-1516
Author(s):  
D. Peano ◽  
M. Chiarle ◽  
J. von Hardenberg
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Climate Variations ◽  
Italian Alps ◽  
Temperature And Precipitation ◽  
Rcp 8.5 ◽  
Glacier Length ◽  
Glacier Modeling ◽  
Model Approach

Abstract. We study the response of a set of glaciers in the Western Italian Alps to climate variations using the minimal glacier modeling approach, first introduced by Oerlemans. The mathematical models are forced over the period 1959–2009, using temperature and precipitation recorded by a dense network of meteorological stations and we find a good match between the observed and modeled glacier length dynamics. Forcing the model with future projections from a state-of-the-art global climate model in the RCP 4.5 and RCP 8.5 scenarios, we obtain a first estimate for the "expiration date" of these glaciers.

Temperature and precipitation in Svalbard 1912–2050: measurements and scenarios

Polar Record ◽  
2002 ◽  
Vol 38 (206) ◽  
pp. 225-232 ◽  
Author(s):  
I. Hanssen-Bauer
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Positive Trend ◽  
Spring Precipitation ◽  
Maximum Increase ◽  
Temperature And Precipitation ◽  
Mean Temperature ◽  
Empirical Downscaling ◽  
The 1960S

AbstractTemperature and precipitation series from Svalbard for the period 1912–2000 were analysed. There was a statistically significant warming from 1912 to the 1930s, a cooling from the 1930s to the 1960s and a warming from the 1960s to present. There was a positive trend in the annual mean temperature during the period 1912–2000, but it was not statistically significant. Spring was the only season when a statistically significant warming was found. For precipitation, statistically significant positive trends during the period 1912–2000 were found on an annual basis and in all seasons except winter. Empirical downscaling was applied on the results from a global climate model to produce scenarios for monthly temperature and precipitation in Svalbard. The 2 m temperature was applied as predictor for temperature. For precipitation, a combination of temperature and sea-level pressure was used. The temperature scenario indicates a warming of about 1°C per decade in winter, and 0.3°C per decade in summer from 1961 to 2050. The projected increase in annual mean temperature is about five times the average warming rate from 1912 to present, and highly significant. The precipitation scenario also indicates that precipitation will increase significantly until 2050. The maximum increase was projected in spring precipitation; however, the trends in seasonal precipitation are quite uncertain.

scholarly journals The value of remote marine aerosol measurements for constraining radiative forcing uncertainty

2020 ◽  
Vol 20 (16) ◽  
pp. 10063-10072 ◽  
Author(s):  
Leighton A. Regayre ◽  
Julia Schmale ◽  
Jill S. Johnson ◽  
Christian Tatzelt ◽  
Andrea Baccarini ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Northern Hemisphere ◽  
Radiative Forcing ◽  
Climate Model ◽  
Global Climate ◽  
Cloud Condensation Nuclei ◽  
Global Climate Model ◽  
Model Parameters ◽  
Marine Aerosol ◽  
Aerosol Emissions

Abstract. Aerosol measurements over the Southern Ocean are used to constrain aerosol–cloud interaction radiative forcing (RFaci) uncertainty in a global climate model. Forcing uncertainty is quantified using 1 million climate model variants that sample the uncertainty in nearly 30 model parameters. Measurements of cloud condensation nuclei and other aerosol properties from an Antarctic circumnavigation expedition strongly constrain natural aerosol emissions: default sea spray emissions need to be increased by around a factor of 3 to be consistent with measurements. Forcing uncertainty is reduced by around 7 % using this set of several hundred measurements, which is comparable to the 8 % reduction achieved using a diverse and extensive set of over 9000 predominantly Northern Hemisphere measurements. When Southern Ocean and Northern Hemisphere measurements are combined, uncertainty in RFaci is reduced by 21 %, and the strongest 20 % of forcing values are ruled out as implausible. In this combined constraint, observationally plausible RFaci is around 0.17 W m−2 weaker (less negative) with 95 % credible values ranging from −2.51 to −1.17 W m−2 (standard deviation of −2.18 to −1.46 W m−2). The Southern Ocean and Northern Hemisphere measurement datasets are complementary because they constrain different processes. These results highlight the value of remote marine aerosol measurements.

Use of Integrated Global Climate Model Simulations and Statistical Time Series Forecasting to Project Regional Temperature and Precipitation

2021 ◽  
Author(s):  
Yuchuan Lai ◽  
David A. Dzombak
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Arima Model ◽  
Climate Change Signal ◽  
Temperature And Precipitation ◽  
Regional Temperature ◽  
Statistical Time

AbstractAn integrated technique combining global climate model (GCM) simulation results and a statistical time series forecasting model (the autoregressive integrated moving average ARIMA model) was developed to bring together the climate change signal from GCMs to city-level historical observations as an approach to obtain location-specific temperature and precipitation projections. This approach assumes that regional temperature and precipitation time series reflect a combination of an underlying climate change signal series and a regional-deviation-from-the-signal series. An ensemble of GCMs is used to describe and provide the climate change signal, and the ARIMA model is used to model and project the regional deviation. Qualitative and quantitative assessments were conducted for evaluating the projection performance of the hybrid GCM-ARIMA (G-ARIMA) model. The results indicate that the G-ARIMA model can provide projected city-specific daily temperature and precipitation series comparable to historical observations and can have improved projection accuracy for several assessed annual indices compared to a commonly used downscaled projection product. The G-ARIMA model is subject to some limitations and uncertainties from the GCM-provided climate change signal. A notable feature of the G-ARIMA model is the efficiency with which projections can be updated when new observations become available, thus facilitating updating of regional temperature and precipitations projections. Given the increasing need for and use of location-specific climate projections in practical engineering applications, the G-ARIMA model is an option for regional temperature and precipitation projection for such applications.

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