| The aims of this study includs analysing of the climate impacts on growing of the Larix gmelinii (Rupr.) Rupr. in Genhe Region where is located in northern area of Da Hinggan Mountains,’explioring the relationships between the climate variations of Genhe Region and some major atmospheric circulation systems in the North Hemisphere, studying the influence of large-scale ocean-atmosphere interactions on Genhe local climate changes. In addition, the close correlations between climate factors and tree-ring width were concerned to reconstructure the longer-term climatic series. Then, climate forecast signals could be got via the periodical analysis. Furthermore, the numerical climate simulation would be used to predicte future climate variations of the Genhe Region, and then, to pre-estimate the future growing trend of the Larix gmelinii (Rupr.) Rupr. The knowledge of dengrochronology, climatology, statistics, numerical cimulation, etc. was utilized in this study. It is a leading research field which includes multi-deciplines and has sentific and acdamic values. The results of this study should be useful in local climate prediction, in facing future climate change and designing forest development stratagies.The cut Larix gmelinii (Rupr.) Rupr. plates and dilled cores used in this study were collected from Genhe primary forests. Firstly, the standard chronologies of Ringwidth, Earlywidth and Latewidth were established by using the ARSTAN program after finish the processes of the WinDENDRO cross dating and the COFECHA tree-ring measurement quality control. The second, the Larix gmelinii (Rupr.) Rupr. Ringwidth responses to Genhe local climate conditions and its nearby region (Genhe Region) are analyzed, the results indicate that some close correlations exist between the Ringwidth and the climate elements for different periods from both previous and contemporary terms. The elements include temperature, surface and deep soil temperatures, snow depth, evaporation, etc. The third, it has been found that the climate variations of the Genhe Region are significant influenced by some major atmospheric circulation systems in Northern Hemisphere. Then, it found also that the previous year sea surface temperature of the northwestern India Ocean is one of the main influential factors that control the evolutionary of those atmospheric circulation systems. The fourth, an annual and deeper soil temperature series of Genhe is reconstructed via employing the Ringwidth. The results of these two series power spectrum reveal about a hundred year,20-year,16-year and7-year variation cycles exist in the two kinds of temperatures. Finally, the outcomes of the climate numerical simulating models were used to forecasting the annual temperatures of Genhe Region for the future30years (from2011to2040). It shows that the temperature would be going up during the following30-year period which phenomenon would be unfavorable to the growing of the Larix gmelinii (Rupr.) Rupr.Main results of this study presented as follows:1. The established standard chronology includes Ringwidth, Earlywidth and Latewidth. Their time-scale lasts for135years (from1876to2010). The COFECHA outputs presents that the averaged coefficiency of all tree-ring samples with the master series reaches to0.626, the mean sensitivity is0.235, the auto-correlation is0.695and the agreement with population chronology is0.951.2. It is found that the Larix gmelinii (Rupr.) Rupr. Ringwidth performs significant negative responses to the annual, Feb-March and Sept-Oct temperatures of the Genhe Region. At the same time, it positively responses to the80cm deep soil temperature of growing season and negatively responses to the Feb-March evaporation and vapor pressure. The negative response to the temperature means that the Larix gmelinii (Rupr.) Rupr. is sensitive to temperature changes of the annual, beginning and ending growing periods. Lower temperature is favorable to the Larix gmelinii (Rupr.) Rupr. Besides, the80cm deep soil temperature of the prior growing season is very helpful to the Larix gmelinii (Rupr.) Rupr. produces wide tree-rings in the following years.3. The annual precipitation of the Genhe Region does not display an up or down trend during the past50years, while the winter-half year precipitation presents a slight increasing trend. The annual, Feb-March and Sept-Oct temperatures, all of them perform a clearly going-up trend. The Genhe decadal mean temperature for2001-2010has increased by1.74℃when comparing to that of1961-1970. Especially for the Feb-March temperature which increased by2.46℃when comparing to those two decades. Conversely to the air temperature, during the term of Sept-Oct, the day amount of the surface temperature below zero decreased by6-7days. Additionally, the40cm and80cm deep soil temperatures shown a higher level in the late half decade of the1970s, and then at a relative lower level during the following decade. Within the next20years, it displays an increasing trend. The winter-half year snow depth increased by6.88cm in the1990s when comparing with the1960s, and added by5.57cm during2001-2010.4. Some close correlations exist between Genhe Region temperature and some major atmospheric circulation systems. From the previous term to current period, a higher temperature normally conducted by an enlarging and strengthening subtropical high, a weak and small North Polar vortex, a shallow East Asian trough, a higher geopotential height over the Tibetan Plateau that means a strong heat source accompanied with a weak India-Burma trough. Conversely, Genhe will have a lower temperature. In spite of this, the Feb-March500hPa charts for both higher and lower temperature years of the Genhe Region present opposite atmospheric circulation patterns over the Eurasian continent. A huge negative anomaly indicates the cold airs act infrequently while the subtropical high was strong and the North Polar vortex was small and weak, that corresponds to a higher temperature year. Oppositely, the Genhe Region experiences a lower temperature year.5. The sea surface temperature of the northwestern India Ocean confirmed to be a crucial impacting factor to the variations of the Genhe Region temperature. The results of the F.OF of the sea surface temperature shown there is a significant correlation existing between the EOF-PC1and the major atmospheric circulation systems. Therefore, it can be concluded that the sea surface temperature changes induce the atmospheric circulation adjustments, and then lead to the Genhe temperature waves. 6. Time-scale of the reconstructed Genhe annual temperature series spans from1913to196, and for the rebuilt Jun-Aug80cm deep soil temperature series is from1913to1074. Both of the reconstructed series are past the sign tests, reduction of the error tests and the parametric tests. Outputs of the power spectrum to both the series reveal long-and short-term variation cycles.7. All of the Hadley and CIMP5numerical climate simulating outcomes for the Genhe Region temperature display an increasing trend for the future30years (from2011to2040). As the model pre-estimating, the temperature of the focused region would increase by about1.01℃in the decade of2031-2040when comparing to the2000s (2001-2010). The increasing temperature would be unfavorable to Larix gmelinii (Rupr.) Rupr. growth. |
PDF Full Text Request