Spatiotemporal changes and modulations of extreme climatic indices in monsoon-dominated climate region linkage with large-scale atmospheric oscillation

2021 ◽  
pp. 105840
Author(s):  
H.M. Touhidul Islam ◽  
Abu Reza Md. Towfiqul Islam ◽  
Md. Abdullah-Al-Mahbub ◽  
Shamsuddin Shahid ◽  
Anjum Tasnuva ◽  
...  
2021 ◽  
Vol 21 (4) ◽  
pp. 3059-3071
Author(s):  
Guocheng Wang ◽  
Zhongkui Luo ◽  
Yao Huang ◽  
Wenjuan Sun ◽  
Yurong Wei ◽  
...  

Abstract. Grassland aboveground biomass (AGB) is a critical component of the global carbon cycle and reflects ecosystem productivity. Although it is widely acknowledged that dynamics of grassland biomass is significantly regulated by climate change, in situ evidence at meaningfully large spatiotemporal scales is limited. Here, we combine biomass measurements from six long-term (> 30 years) experiments and data in existing literatures to explore the spatiotemporal changes in AGB in Inner Mongolian temperate grasslands. We show that, on average, annual AGB over the past 4 decades is 2561, 1496 and 835 kg ha−1, respectively, in meadow steppe, typical steppe and desert steppe in Inner Mongolia. The spatiotemporal changes of AGB are regulated by interactions of climatic attributes, edaphic properties, grassland type and livestock. Using a machine-learning-based approach, we map annual AGB (from 1981 to 2100) across the Inner Mongolian grasslands at the spatial resolution of 1 km. We find that on the regional scale, meadow steppe has the highest annual AGB, followed by typical and desert steppe. Future climate change characterized mainly by warming could lead to a general decrease in grassland AGB. Under climate change, on average, compared with the historical AGB (i.e. average of 1981–2019), the AGB at the end of this century (i.e. average of 2080–2100) would decrease by 14 % under Representative Concentration Pathway (RCP) 4.5 and 28 % under RCP8.5. If the carbon dioxide (CO2) enrichment effect on AGB is considered, however, the estimated decreases in future AGB can be reversed due to the growing atmospheric CO2 concentrations under both RCP4.5 and RCP8.5. The projected changes in AGB show large spatial and temporal disparities across different grassland types and RCP scenarios. Our study demonstrates the accuracy of predictions in AGB using a modelling approach driven by several readily obtainable environmental variables and provides new data at a large scale and fine resolution extrapolated from field measurements.


2012 ◽  
Vol 482-484 ◽  
pp. 372-375 ◽  
Author(s):  
Jing Cai Wang ◽  
Zi Qiang Xia ◽  
Ji Xing Wang ◽  
Zhi Hua Lu

An in situ field test with three indices of stability, sensitivity and accuracy on 12 soil moisture sensors was carried out in a sandy loam soil located in Lu’an at the subtropical monsoon climate region (China). The results showed that the majority of sensors were above 0.98 with a higher stability degree except for HT-DR-601(0.348) and DZN3 (0.661). Almost all sensors had a sensitive response to a certain amount of precipitation but Hydra Probe II was an exception. Trime-pico, SM300, ML2X, SWR6 and DH-FDR had a higher accuracy than 0.785, while DZN3 and HT-DR-601 were very lower. The mean differences of SM300, Trime-pico and Uni_SM were between -1% and 0, while HTSMS-02, DH-FDR, SWR6, ML2X, MP-4C and MP-323 were between -5% and -1%. DZN3 had the largest values of -17.8%. Finally, SM300, Trime-pico, ML2X, SWR6 and DH-FDR were got scores above 9 points while MP-323 and Uni_SM were above 8.4, showing an outstanding performance. The field performance study could provide some choices for the large-scale filed applications and the drought monitoring system.


Author(s):  
A. C. O. Martins ◽  
M. C. A. Silva ◽  
A. D. Benetti

Abstract This study aimed at providing a set of optimal kinetic and stoichiometric parameters of ASM1 representative of wastewater from a subtropical climate region in Brazil. ASM1 was applied on STOAT program, and the model parameters were evaluated and optimized with sensitivity analysis and Response Surface Methodology (RSM) to reach minimum prediction errors of effluent TSS, COD, and NH3. Six sensitive parameters were identified: YH, YA, μA, KNH, bA, and kOA. Predictions of RSM regression models were strongly correlated to the STOAT predictions. YH mainly affected TSS and COD, and the other parameters affected NH3. ASM1 calibration with estimated optimal values of sensitive parameters resulted in approximately null prediction errors for modeling state variables. NH3 presented similar results in the ASM1 validation; meanwhile, TSS and COD presented high errors related to the increase in YH due to the RSM optimization. The optimal parameters, mainly YA, μA, KNH, bA, and kOA, constitute references for other studies on ASM1 modeling using wastewater data from a subtropical climate region. YH optimal value should be evaluated as well as the effect of sludge wastage methods and the simulation periods.


2020 ◽  
Vol 10 (17) ◽  
pp. 5790
Author(s):  
Francisco Criado-Aldeanueva ◽  
Javier Soto-Navarro

The Mediterranean Sea, strategically situated across a dynamic frontier line that separates two regions with different climates (Europe and North Africa), has been the focus of attention of many studies dealing with its thermohaline circulation, deep water formation processes or heat and freshwater budgets. Large-scale atmospheric forcing has been found to play an important role in these topics and attention has been renewed in climatic indices that can be used as a proxy for atmospheric variability. Among them, the North Atlantic oscillation, the East Atlantic or the East Atlantic–West Russia patterns have been widely addressed but much less attention has been devoted to a Mediterranean mode, the Mediterranean oscillation. This overview summarizes the recent advances that have been achieved in the understanding of these climatic indices and their influence on the functioning of the Mediterranean from a physical point of view. The important role of the Mediterranean oscillation is emphasized and the most relevant aspects of the other indices are revisited and discussed.


2014 ◽  
Vol 15 (2) ◽  
pp. 650-663 ◽  
Author(s):  
Francisco Criado-Aldeanueva ◽  
F. Javier Soto-Navarro ◽  
Jesús García-Lafuente

Abstract Interannual to interdecadal precipitation P, evaporation E, freshwater budget (E − P), and air–sea net heat flux Q have been correlated with the North Atlantic Oscillation (NAO), eastern Atlantic (EA), eastern Atlantic–western Russia (EA-WR), and Mediterranean Oscillation (MO) climatic indices to explore the influence of atmospheric forcing in the Mediterranean freshwater and heat budget variability. The effect of the MO pattern has similarities with that of the NAO, but MO influence is more intense. On an annual basis, the MO index gives the highest correlation with all the variables considered, and during its negative phase, it exerts a stronger influence than the NAO and is associated with higher P and, especially, enhanced evaporative losses in the Levantine subbasin. The EA pattern does not significantly affect P in the Mediterranean, but a high correlation is found for E and Q from 1979. The EA-WR mode plays a significant role in annual net heat flux since variations in its sign have the potential to induce seesaw variations in the heat budgets of the eastern and western subbasins, as previously found by Josey et al., for wintertime.


Author(s):  
Bonosri Ghose ◽  
Abu Reza Md. Towfiqul Islam ◽  
Roquia Salam ◽  
Shamsuddin Shahid ◽  
Mohammad Kamruzzaman ◽  
...  

1985 ◽  
Vol 33 (6) ◽  
pp. 677 ◽  
Author(s):  
H Wood ◽  
R Degabriele

Natural populations of Echium plantagineum on an east-west line across south-eastern Australia were sampled on three occasions during the growing season, and seeds collected from individual plants in each population were grown in a common glasshouse. In another experiment seedlings of E. plantagineum were divided and clones from each plant were grown under two soil moisture regimes. Field populations differed significantly in all seven characters measured at all sampling dates but, with one exception, between-population differences were unrelated to five climatic indices. Glasshouse populations differed significantly in 15 of 27 characters; variations in some of these characters were related by regression analysis to one or more of the climatic indices. Clones grown under moisture stress flowered later, had proportionally wider leaves and were smaller than well watered clones. The data suggest that an ecocline has developed, or is developing, in E. plantagineum in south- eastern Australia in response to large-scale and long-term aspects of climate, although extensive genetic variation between individuals in each population was also observed. This species exhibits a great deal of phenotypic plasticity in response to localized environmental factors.


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