| 1. |
- Chen, Deliang, 1961, et al.
(author)
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Projecting future local precipitation and its extremes for Sweden
- 2015
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In: Geografiska Annaler. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 97:1, s. 25-39
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Journal article (peer-reviewed)abstract
- A procedure to obtain future local precipitation characteristics focused on extreme conditions has been developed based on a weather generator. The method involves six major steps: (1) the weather generator was calibrated using observed daily precipitation at 220 Swedish stations during 1961–2004; (2) present and future daily precipitation characteristics for the Swedish stations from two global climate models, namely ECHAM5 and HadCM3, were used to calculate weather generator parameters for the present and future climates at global climate model spatial scales; (3) the ratio of the weather generator parameters for the present climate simulated by the global climate models to those calculated for each station falling into the global climate model grid box were computed for all the stations; (4) these ratios were also assumed to be valid in the future climate, that way the future parameters for each station for the global climate model projected future climate could be calculated; (5) using the estimated future parameters of the weather generator, the future daily precipitation at each station could be simulated by the weather generator; (6) the simulated daily precipitation was used to compute eight indices describing mean and extreme precipitation climates. The future mean and extreme precipitation characteristics at the stations under the Second Report on Emission Scenarios A2 scenario were obtained and presented. An overall increasing trend for frequency and intensity of the indices are identified for the majority of the stations studied. The developed downscaling methodology is relatively simple but useful in deriving local precipitation changes, including changes in the precipitation extremes.
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| 2. |
- Irannezhad, M., et al.
(author)
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Impacts of changes in climate and land cover-land use on flood characteristics in Gorganrood Watershed (Northeastern Iran) during recent decades
- 2018
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In: Geografiska Annaler Series a-Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 100:4, s. 340-350
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Journal article (peer-reviewed)abstract
- This study evaluated the effects of changes in climate and land cover-land use (LCLU) on flood intensity and frequency in the Gorganrood Watershed (GW) located in the northeast of Iran during recent decades. For this purpose, hydroclimatic (precipitation, temperature, and river discharge) time series recorded at nine stations placed in the GW during 1973-2014 were used. Flood characteristics in terms of mean, maximum and number of peaks at five discharge stations (Galikash, Gonbad, Huji Ghushan, Tamar, and Tangrah) sited in the outlet of GW sub-basins were determined applying the Peak-Over-Threshold (POT) method to daily specific discharges. This is designed to remove the effect of the different size of sub-basins. The whole study period was divided into three 14-years segments (1973-1986, 1987-2000 and 2001-2014) based on satellite LCLU maps produced for 1973, 1986, 2000 and 2014. In the GW and its sub-basins during recent decades, both flood intensity and frequency increased, the climate became wetter and warmer, and LCLU mostly converted from rangeland to farmland. The partial correlation analyses identified that flood frequency in GW was primarily connected to the LCLU conversions, but moderately to observed wetter and warmer climate. Similarly, the Tamar sub-basin experienced effects of LCLU and climate on the maximum and the number of peaks. In Haji Ghushan, wetter and warmer climate resulted in more intense and frequent floods. Increases in precipitation appear to have played the most important role in the higher flood frequency in Galikash.
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| 3. |
- Irannezhad, MASOUD, et al.
(author)
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THE ROLE OF ATMOSPHERIC CIRCULATION PATTERNS IN AGROCLIMATE VARIABILITY IN FINLAND, 1961–2011
- 2016
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In: Geografiska Annaler, Series A: Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 98:4, s. 287-301
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Journal article (peer-reviewed)abstract
- © 2016 Swedish Society for Anthropology and GeographyThis study evaluates interannual variations and trends in growing season daily temperature sum and daily precipitation sum in Finland during 1961–2011, and their connections to well known atmospheric circulation patterns. Changes in summer (June–August) climate partially explain changes in growing season daily temperature sum and daily precipitation sum over Finland, which naturally decreased from south to north. On a national scale, growing season warmed and became wetter during 1961–2011, as growing season daily temperature sum and daily precipitation sum significantly (p < 0.05) increased by 5.01 ± 3.17°C year–1 and 1.39 ± 0.91 mm year–1, respectively. The East Atlantic pattern was the most influential atmospheric circulation pattern for variations in growing season daily temperature sum (rho = 0.40) across Finland and the East Atlantic/West Russia pattern was most influential for growing season daily precipitation sum variability (rho = –0.54). There were significant (p < 0.05) increasing trends in growing season daily temperature sum and daily precipitation sum throughout Finland during 1961–2011. Increased growing season daily temperature sum was mainly observed in northern, central, western, eastern and coastal areas of south-western Finland. This warming was positively associated with the East Atlantic pattern in the north, centre and south, but negatively associated with the East Atlantic/West Russia pattern in eastern Finland. Increased GSP mostly occurred in southern, eastern, western, central, northern and north-western Finland. These wetting trends were positively correlated with the East Atlantic pattern in the north and negatively correlated with the Polar pattern in the south and the East Atlantic/West Russia pattern in the east, west, centre and north-east of Finland. The overall agroclimatic year-to-year variability in Finland between 1961 and 2011 was mostly linked to variations in the East Atlantic and East Atlantic/West Russia patterns.
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| 4. |
- Wang, F., et al.
(author)
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Global and regional climate responses to national-committed emission reductions under the Paris agreement
- 2018
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In: Geografiska Annaler Series a-Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 100:3, s. 240-253
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Journal article (peer-reviewed)abstract
- To stabilize global mean temperature change within the range of 1.5-2.0 degrees C in accordance with the Paris Agreement, countries worldwide submitted their Intended Nationally Determined Contributions with their proposed emission reductions. However, it remains unclear what the resulting climate change in terms of temperature and precipitation would be in response to the Intended Nationally Determined Contribution emission efforts. This study quantifies the global and regional temperature and precipitation changes in response to the updated Intended Nationally Determined Contribution scenarios, using simulations of 14 Fifth Coupled Climate Model Intercomparison Project models. Our results show that Intended Nationally Determined Contribution emissions would lead to a global mean warming of 1.4 degrees C (1.3-1.7 degrees C) in 2030 and 3.2 degrees C (2.6-4.3 degrees C) in 2100, above the preindustrial level (the 1850-1900 average). Spatially, the Arctic is projected to have the largest warming, 2.5 and 3 times the global average for 2030 and 2100, respectively, with strongest positive trends at 70-85 degrees N over Asia, Europe and North America (6.5-9.0 degrees C). The excessive warming under Intended Nationally Determined Contribution scenarios is substantially above the 1.5 degrees C or 2.0 degrees C long-term stabilization level. Global mean precipitation is projected to be similar to preindustrial levels in 2030, and an increase of 6% (4-9%) by 2100 compared with the preindustrial level. Regional precipitation changes will be heterogeneous, with significant increases over the equatorial Pacific (about +120%) and strong decreases over the Mediterranean, North Africa and Central America (-15% - -30%). These results clearly show that it is necessary to adjust and strengthen national mitigation efforts on current Intended Nationally Determined Contributions to meet the long-term temperature target.
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