An Assessment of Temperature and Precipitation Change Projections using a Regional and a Global Climate Model for the Baro-Akobo Basin, Nile Basin, Ethiopia

2013 ◽  
Vol 04 (01) ◽  
Author(s):  
Asfaw Kebede
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Precipitation Change ◽  
Nile Basin ◽  
Temperature And Precipitation

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.

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.

scholarly journals Implications of global warming for the climate of African rainforests

2013 ◽  
Vol 368 (1625) ◽  
pp. 20120298 ◽  
Author(s):  
Rachel James ◽  
Richard Washington ◽  
David P. Rowell
Keyword(s):  
Global Warming ◽  
Amazon Basin ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Global Temperature ◽  
Congo Basin ◽  
Coupled Models ◽  
Temperature And Precipitation ◽  
Equatorial Africa

African rainforests are likely to be vulnerable to changes in temperature and precipitation, yet there has been relatively little research to suggest how the regional climate might respond to global warming. This study presents projections of temperature and precipitation indices of relevance to African rainforests, using global climate model experiments to identify local change as a function of global temperature increase. A multi-model ensemble and two perturbed physics ensembles are used, one with over 100 members. In the east of the Congo Basin, most models (92%) show a wet signal, whereas in west equatorial Africa, the majority (73%) project an increase in dry season water deficits. This drying is amplified as global temperature increases, and in over half of coupled models by greater than 3% per °C of global warming. Analysis of atmospheric dynamics in a subset of models suggests that this could be partly because of a rearrangement of zonal circulation, with enhanced convection in the Indian Ocean and anomalous subsidence over west equatorial Africa, the Atlantic Ocean and, in some seasons, the Amazon Basin. Further research to assess the plausibility of this and other mechanisms is important, given the potential implications of drying in these rainforest regions.

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 Future shift in winter streamflow modulated by internal variability of climate in southern Ontario

2019 ◽  
Author(s):  
Olivier Champagne ◽  
Altaf Arain ◽  
Martin Leduc ◽  
Paulin Coulibaly ◽  
Shawn McKenzie
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Internal Variability ◽  
Early Spring ◽  
Large Ensemble ◽  
Fluvial Systems ◽  
Southern Ontario ◽  
Temperature And Precipitation

Abstract. Fluvial systems in southern Ontario are regularly affected by widespread early-spring flood events primarily caused by rain-on-snow events. Recent studies have shown an increase in winter floods in this region due to increasing winter temperature and precipitation. Streamflow simulations are associated with uncertainties tied to the internal variability of climate. These uncertainties can be assessed using hydrological models fed by downscaled Global Climate Model Large Ensemble (GCM-LE) data. The Canadian Regional Climate Model Large Ensemble (CRCM5-LE), a dynamically downscaled version of a GCM-LE, was developed to simulate climate variability over northeastern North America under different future climate scenarios. In this study, CRCM5-LE temperature and precipitation projections under RCP 8.5 scenario were used as input in the Precipitation Runoff Modelling System (PRMS) to simulate near future (2040s) streamflow for four watersheds in southern Ontario. Model simulations show that 14 % of the ensemble project a high (low) increase of streamflow volume in January-February. Streamflow increases may be driven by rain and snowmelt modulation caused by the development of high (low) pressure anomalies in North America’s East Coast. Additionally, the streamflow may be enhanced by high pressure circulation patterns directly over the Great Lakes creating warm conditions and increasing snowmelt and rainfall/snowfall ratio (16 %). These results are important to assess the internal variability of the hydrological projections and to inform society of increased winter streamflow.

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.

High bit rate ACTS experiments for performing global science - Keck Telescope and global climate model

1996 ◽  
Author(s):  
Larry Bergman ◽  
J. Gary ◽  
Burt Edelson ◽  
Neil Helm ◽  
Judith Cohen ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Bit Rate ◽  
Global Science ◽  
High Bit Rate

scholarly journals A comparison of ship and satellite measurements of cloud properties with global climate model simulations in the southeast Pacific stratus deck

2010 ◽  
Vol 10 (14) ◽  
pp. 6527-6536 ◽  
Author(s):  
M. A. Brunke ◽  
S. P. de Szoeke ◽  
P. Zuidema ◽  
X. Zeng
Keyword(s):  
Diurnal Cycle ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Cloud Fraction ◽  
Cloud Base ◽  
Liquid Water Path ◽  
Cloud Properties ◽  
Southeast Pacific ◽  
Cloud Thickness

Abstract. Here, liquid water path (LWP), cloud fraction, cloud top height, and cloud base height retrieved by a suite of A-train satellite instruments (the CPR aboard CloudSat, CALIOP aboard CALIPSO, and MODIS aboard Aqua) are compared to ship observations from research cruises made in 2001 and 2003–2007 into the stratus/stratocumulus deck over the southeast Pacific Ocean. It is found that CloudSat radar-only LWP is generally too high over this region and the CloudSat/CALIPSO cloud bases are too low. This results in a relationship (LWP~h9) between CloudSat LWP and CALIPSO cloud thickness (h) that is very different from the adiabatic relationship (LWP~h2) from in situ observations. Such biases can be reduced if LWPs suspected to be contaminated by precipitation are eliminated, as determined by the maximum radar reflectivity Zmax>−15 dBZ in the apparent lower half of the cloud, and if cloud bases are determined based upon the adiabatically-determined cloud thickness (h~LWP1/2). Furthermore, comparing results from a global model (CAM3.1) to ship observations reveals that, while the simulated LWP is quite reasonable, the model cloud is too thick and too low, allowing the model to have LWPs that are almost independent of h. This model can also obtain a reasonable diurnal cycle in LWP and cloud fraction at a location roughly in the centre of this region (20° S, 85° W) but has an opposite diurnal cycle to those observed aboard ship at a location closer to the coast (20° S, 75° W). The diurnal cycle at the latter location is slightly improved in the newest version of the model (CAM4). However, the simulated clouds remain too thick and too low, as cloud bases are usually at or near the surface.

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