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1

Picea schrenkiana tree-ring chronologies development and vegetation index reconstruction for the Alatau Mountains, Central Asia

Zhang T., Zhang R., Lu B., Mambetov B. T., Kelgenbayev N., Dosmanbetov D., Maisupova B., Chen F., Yu S., Shang H., Huang L.

Geochronometria

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2018

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Vol. 45, no. 1

107--118

EN

In this study, a total of 176 tree cores from Schrenk spruce (Picea schrenkiana) were used to establish a tree-ring chronology and a 167-year July–October normalized differential vegetation index (NDVI) for the Alatau Mountains in Central Asia was reconstructed using this newly developed chronology. The tree-ring based NDVI reconstruction tracks the observed data well (r=0.577, p<0.01, n=25) and precisely captures the drought events recorded in historical documents that occurred over a large area in 1917 and 1938. After applying a 21-year moving average, three dense (1860–1870, 1891–1907, and 1950–1974) and three sparse (1871–1890, 1908–1949, and 1975–2006) vegetation coverage periods were found in this reconstruction. Spatial correlation proves that the reconstructed NDVI series contains climatic signals representative for a large area including southern Kazakhstan. Although a comparison between this reconstruction and four climatic reconstructions for southeastern Kazakhstan, Nilka (in the Ili region), the Issyk Lake, and the Aksu region reveals similar variations, the coherence between these reconstructions become weak with the increase in spatial distance from north to south. In addition to the local representation, it was also demonstrated that the newly developed NDVI index can indicate the large-scale circulations over Eurasia, with the higher NDVI associated with stronger westerly winds from the Atlantic to the Alatau Mountains, and the lower NDVI associated with the weaker winds.

2

Development of a Larix principis-rupprechtii tree-ring width chronology and its climatic signals for the southern Greater Higgnan Mountains

Zhang T., Yu S., Yuan Y., Huang L., Jiang S.

Geochronometria

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2018

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Vol. 45, no. 1

1--9

EN

Forty-one living larch (Larix principis-rupprechtii) trees collected from two sampling sites in 1310–1530 m a.s.l. in the southern Greater Higgnan Mountains in the northeastern China are used to develop a regional tree-ring width chronology. The credible chronology spans 185 years from 1830 to 2014. The results of correlation analyses indicate that moisture is the main climatic factor controlling radial growth of larch trees in this mountainous area. Spatial correlation proves that the regional tree-ring width chronology contains climatic signals representative for a large area including the eastern Mongolian Plateau and Nuluerhu Mountains. A comparison between the newly developed chronology and a May–July Palmer Drought Severity Index (PDSI) reconstruction for the Ortindag Sand Land reveals similar variations, particularly in the low-frequency domain. The tree-ring records also capture a severe and sustained drying trend recorded in the 1920s across a wide area of northern China.

3

Assessment of usefulness of the mems-based integrated navigation unit in car navigation

Uradziński M., Rapiński J., Tomaszewski D., Śmieja M., Guo H., Yu S., Jian X.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2017

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nr 20(4)

321--331

EN

Due to the development of MEMS, there is an opportunity to build a low-cost integrated navigation systems, operating independently of horizon visibility. This paper presents the proposal of an integrated GPS/IMU platform using MEMS technology. In order to verify the performance of a system built at the University of Warmia and Mazury, an experiment was conducted. In this experiment a precise Javad GNSS receiver, commercial grade GPS/IMU XW – ADU5660 and own-built system were used. The experiment was conducted to compare the results obtained from self built device with the working military integrated navigation unit. During the study all three devices were mounted inside moving vehicle. The car drove route inside the Kortowo campus, during which, all equipment performed measurements. Then, the results from both integrated systems were compared with RTK (Real Time Kinematic) results from Javad receiver. Experiments prove that the performance of own device is comparable to the commercial device.

4

Sea ice management for oil and gas platforms in the Bohai Sea

Zhang D., Yu S., Wang Y., Yue Q.

Polish Maritime Research

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2017

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S 2

195--204

EN

Bohai is a typical marginal oil field in an ice region, where most of the oil and gas platforms are economical. Sea ice is the main factor that affects the safety of oil and gas platforms in Bohai. Due to the complexity of the ice load and ice-induced vibrations, there are large security risks when developing Bohai oil and gas in the winter. It is difficult to ensure the safe production of oil and gas in winter using existing sea ice disaster warning technologies. Based on winter oil and gas production in the Bohai Sea’s Liaodong Bay, a set of suitable sea ice management systems is proposed in this paper. These systems integrate sea ice monitoring, risk assessment and risk prediction technologies. Based on the risk warning system, an ice management model of a Bohai ice platform has been put into practice, which ensures the safe production of the platform in winter.

5

Numerical analysis on Rib-tubes of seawater open rack vaporizer with the spoiler lever

Su H., Yu S., Fan J., Xing W.

Polish Maritime Research

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2017

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S 2

14--21

EN

In order to explore a more reasonable structure and operating parameter, guide the design and improve the gasification of seawater Open Rack Vaporizer (ORV), Research on the rules of seawater that flows and heat transfer in the ORV tube was studied in this paper. By simplifying the model, heat transfer tube model with spoiler lever was obtained and simulated, the distribution of temperature field, gas ratio, velocity field and press field in rib tube were analyzed, and different inlet velocity of LNG, roughness of the tube wall both effected on the overall gasification, the results shows that the actual gasification efficiency from heat transfer tube is higher than normal, small difference of gas ratio outlet, velocity and temperature are both lower, LNG could be easer gasified at operating temperature between -162°C~+3°C than that between -162°C~+0°C.

6

General concerns life-cycle design of economical ice-resistant structures in the Bohai Sea

Zhang D., Yu S., Yue Q.

Polish Maritime Research

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2017

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S 2

164--191

EN

In China, the oil and natural gas resources of Bohai Bay are mainly marginal oil fields. It is necessary to build both iceresistant and economical offshore platforms. However, there are many risks during the life cycle of offshore platforms due to the imperfect preliminary design for the Bohai Sea economical ice-resistant structures. As a result, the whole life-cycle design should be considered, including plan, design, construction, management and maintenance design. Based on the demand of existing codes and research of the basic design, structural ice-resistant performance and the reasonable management and maintenance, the life-cycle design theory is discussed. It was concluded that the life-cycle cost-effective optimum design proposed will lead to a minimum risk.

7

Flotation separation of cervantite from quartz

Wang J., Hua Y., Yu S., Xiao J., Xu L., Wang Z.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

1119--1132

EN

Flotation separation of cervantite (Sb2O4) from quartz was investigated using dodecylamine (DDA) as a collector. Experiments were conducted on single minerals and on a synthetic mixture of quartz and cervantite. Flotation separation mechanisms were investigated using the zeta potential technique, solution chemistry principles, density functional calculations and Fourier Transform Infrared (FT-IR) spectroscopy. The results indicated that DDA, primarily in the form of molecules, exhibited excellent performance in flotation of cervantite and quartz at pH 10.5. The adsorption energy of the DDA molecules on the cervantite surface was greater than the adsorption energy of water molecules, while the adsorption energy of DDA on the quartz surface was less than the adsorption energy of water molecules. DDA molecules can be adsorbed on the quartz surface to a certain extent, but it was difficult for the same molecule to be adsorbed on the cervantite surface in the pulp. This resulted in flotation of quartz. DDA molecules were adsorbed on quartz not only through physical adsorption but also by hydrogen bonding. However, cervantite could not be floated at pH 10.5 since adsorption of DDA molecules occurred through weak physical bonds on cervantite.

8

The research on characteristic parameters and resistance chart of operation and maintenance trimaran in the sea

Chen Y., Yang L., Xie Y., Yu S.

Polish Maritime Research

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2016

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S 1

20--24

EN

The paper determined the volume ratio of the main hull and side hull and their position characteristic parameter of operation and maintenance trimaran. Numerical simulation technology was used to do the analysis and calculation of trimarans which have different volume ratio of the main and side hull, and on this basis, the paper tried different positions of main and side hull, finally got the trimaran with optimum resistance performance and the chart of trimaran resistance estimation, so as to provide a new way in the selection of feature parameter of offshore wind farm maintenance trimaran and its resistance estimation.

9

Tree-Ring Response to Snow Cover and Reconstruction of Century annual Maximum Snow Depth for Northern Tianshan Mountains, China

Qin L., Yuan Y., Zhang R., Wei W., Yu S., Fan Z., Chen F., Zhang T., Shang H.

Geochronometria

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2016

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Vol. 43, no. 1

9--17

EN

Heavy snowfall and extreme snow depth cause serious losses of human life and property in the northern Tianshan Mountains almost every winter. Snow cover is an important indicator of climate change. In this study, we developed five tree-ring-width chronologies of Schrenk spruce (Picea schrenkiana Fisch. et Mey) from the northern Tianshan Mountains using standard dendrochronological methods. Correlation analyses indicated that radial growth of trees in the northern Tianshan Mountains is positively affected by annual maximum snow depth. This relationship was validated and models of annual maximum snow depth back to the 18th century were developed. The reconstruction explains 48.3% of the variance in the instrumental temperature records during the 1958/59–2003/04 calibration periods. It indicates that quasi-periodic changes exist on 2.0–4.0-yr, 5.3-yr, 14.0-yr, and 36.0-yr scales. The reconstructed series shows that maximum snow depth exhibits obvious stages change, the periods characterized by lower maximum snow depth were 1809/10–1840/41, 1873/74– 1893/94, 1909/10–1929/30, 1964/65–1981/82, and the periods characterized by higher maximum snow depth were 1841/42–1872/73, 1894/95–1908/09, 1930/31–1963/64, and 1982/83–present. The lower period of annual maximum snow depth during the 1920s–1930s is consistent with the severe drought that occurred at this time in northern China. From the 1970s to the present, the maximum snow depth has increased clearly with the change to a warmer and wetter climate in Xinjiang. The reconstruction sheds new light on snow cover variability and change in a region where the climate history for the past several centuries is poorly understood.

10

Deblending of Simultaneous-source Seismic Data using Fast Iterative Shrinkage-thresholding Algorithm with Firm-thresholding

Qu S., Zhou H., Liu R., Chen Y., Zu S., Yu S., Yuan J., Yang Y.

Acta Geophysica

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2016

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Vol. 64, no. 4

1064--1092

EN

In this paper, an improved algorithm is proposed to separate blended seismic data. We formulate the deblending problem as a regularization problem in both common receiver domain and frequency domain. It is suitable for different kinds of coding methods such as random time delay discussed in this paper. Two basic approximation frames, which are iterative shrinkage-thresholding algorithm (ISTA) and fast iterative shrinkage-thresholding algorithm (FISTA), are compared. We also derive the Lipschitz constant used in approximation frames. In order to achieve a faster convergence and higher accuracy, we propose to use firm-thresholding function as the thresholding function in ISTA and FISTA. Two synthetic blended examples demonstrate that the performances of four kinds of algorithms (ISTA with soft- and firm-thresholding, FISTA with soft- and firm-thresholding) are all effective, and furthermore FISTA with a firm-thresholding operator exhibits the most robust behavior. Finally, we show one numerically blended field data example processed by FISTA with firm-thresholding function.

11

Preparation and electromagnetic properties of zinc ferrite/expanded graphite composites

Shen G., Yu S., Cao Y.

Materials Science Poland

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2014

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Vol. 32, No. 3

470--474

EN

An effective process for the synthesis of nano spinel zinc ferrite/expanded graphite composites was developed in order to get an electromagnetic interference shielding material. Firstly, expandable graphite was prepared using sulfuric and nitric acid solutions. Then, the precursor of the composites was produced by chemical co-precipitation method, followed by heating treatment. The obtained composites were characterized by X-ray diffraction and scanning electron microscopy. The dielectric and magnetic properties were determined using vector network analyzer and vibrating sample magnetometry. The results showed that ferrite nanoparticles with the sizes of about 50–150 nm were uniformly dispersed on the surface and interspace of EG. The magnetic properties of the composites changed by adjusting the ferrite/EG ratio and the composites had high dielectric constant in the range of 2–18 GHz. These properties of the prepared composites suggest that they can be used as a promising electromagnetic interference shielding material.

12

Tree-ring based temperature reconstruction for the west Qinling Mountains (China): linkages to the High Asia, solar activity and Pacific-Atlantic Ocean

Chen F., Yuan Y., Wei W., Yu S., Shang H., Zhang T., Zhang R., Wang H., Qin L.

Geochronometria

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2014

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Vol. 41, no. 3

234--244

EN

We developed a Faxon fir (Abies faxoniana) tree-ring width chronology at the timberline in the western Qinling Mountains, China. Herein February–July mean temperature was reconstructed for Zhouqu in the western Qinling Mountains back to AD 1650 based on the standard chronology. The climate/tree-growth model accounts for 43.5% of the instrumental temperature variance during the period 1972–2006. Spatial correlation analyses with the gridded temperature data shows that the tem-perature reconstruction captures regional climatic variations over central and southeast China, and strong teleconnections with the nearby High Asia. There is a good agreement with cold and warm pe-riods previously estimated from tree-rings in Nepal, India and southwest China. The temperature re-construction indicates that there was pronounced cooling in Zhouqu during the Maunder Minimum (late 1600s to early 1700s). The cold period (1813–1827) of the temperature reconstruction coincide with the volcanic eruptions. Significant spectral peaks are found at 56.9, 22.3, 11.4, 2.9, 2.8, 2.6, 2.2 and 2.0 years. The spatial correlation patterns between our temperature reconstruction and SSTs of the Atlantic and Pacific Oceans suggest a connection between regional temperature variations and the atmospheric circulations. It is thus revealed that the chronology has enough potential to reconstruct the climatic variability further into the past.

13

Simultaneous determination of gallic acid, protocatechuic acid, catechin, epicatechin, quercetin and kaempferol in Chinese chestnut (Castanea mollissima blume) kernel by high-performance liquid chromatography with diode array detection

Wang T., Yang Y. D., Du B., Yu S., Hou W. L.

Acta Chromatographica

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2014

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Vol. 26, no. 3

539--550

EN

Chestnut exhibits anti-inflammatory, styptic, anti-diarrhea, and analgestic effects as a traditional Chinese medicine. There is increasing evidence that shows that the consumption of chestnuts has become more important in human nutrition due to the health benefits provided by the antioxidants. The phenolic compounds are responsible for major bioactivities, such as anti-tumor and anti-oxidation. A high-performance liquid chromatography (HPLC) method with diode array detection (DAD) was established for the simultaneous determination of six phenolic compounds (gallic acid, GA; protocatechuic acid, PR; catechin, CA; epicatechin, EP; quercetin, QU; kaempferol, KA) in Chinese chestnut (Castanea mollissima blume) kernel. The sample followed by separation on Eclipse XDB-C18 column (150 × 4.6 mm, id., 5 μm) with gradient elution of methanol-1.0% acetate acid solution as a mobile phase, at a temperature of 30°C, under the ratio of 1.2 mL min-1, with 5 μL injection volume, and multi-wavelength synthesis was used with DAD. The correlation coefficients were larger than 0.999, the recoveries were 97.58% for GA, 100.41% for PA, 96.23% for CA, 101.38% for QU, 99.15% for EP, and 98.60% for KA, relative standard deviation (RSD) were 1.04% for GA, 1.21% for PA, 1.09% for CA, 1.19% for QU, 1.06% for EP, and 1.20% for KA. This method was applied for the determination of phenolics in chestnut kernel and was found to be fast, sensitive, and suitable.

14

Study on The Key Technologies of On-line Monitoring of Transformer Winding Deformation Based on Short-circuit Reactance Analysis

Rui C., Yongfen L., Yanming L., Yu S., Ling R., Wei L.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 9

302-305

EN

The research about on-line monitoring of transformer winding deformation based on Short-Circuit Reactance is studied, then a method is put forward to calculate the leakage reactance of power transformer quickly. The equivalent resistance can be got from the ratio of voltage difference and current at the peak of current. Also, the equivalent inductance can be got from the ratio of voltage difference and current differential when current is zero. At the same time, it is helpful for improving the resolution of the algorithm to the maximum precision of AD acquisition card by magnifying the voltage difference of primary and secondary voltage before being gathered to AD card. The system designed by the two technologies above is tested on the laboratory platform and a criterion is proposed to help to judge the state of winding. The article provides an effective method to monitor on-line monitor the winding deformation of transformer.

PL

W artykule przedstawiono metodę monitorowania w trybie on-line deformacji uzwojeń transformatora. Do analizy wykorzystano pomiar reaktancji w stanie krótkotrwałego zwarcia. Określana jest też zastępcza rezystancja i indukcyjność uzwojenia. Badania eksperymentalne potwierdziły skuteczność metody.

15

Equivalent Multi-Surge Impedance Model of Transmission Line Towers

Du L., Yu S., Mi X., Yang Q., Wang Y.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 12a

259-263

EN

To analyze exactly the wave propagation processes of a transmission tower when lightning strikes, an equivalent model of a transmission tower was studied in this paper. First, based on the correlative theory of tapered antenna, an equivalent surge impedance model of a single stanchion of tower was made. This tower was regarded as a four-conductor system according to the real configuration of a tower, and the equivalent impedance of the four-conductor system was obtained by multiplying the single pillar impedance with the compensation factor. Combined with the definition of wave impedance regarded with inductance and capacitance, the compensation factor of the four-conductor system was introduced. Then, the bracings equivalent model was obtained based on the analysis of the effect of bracings on the main body of a tower, and an equivalent impedance model of the crossarms was built base on the correlation theory of the equivalent model of parallel multi-conductors. In modularizing the tower model, the equivalent impedance of the tower was found. Finally, a 500 kV tower was calculated in this paper using the equivalent impedance model of the tower.

PL

W artykule przedstawiono badania propagacji fali w energetycznej wieży transmisyjnej, po uderzeniu pioruna. Analizę przeprowadzono na podstawie modułowego modelu anteny w dwóch etapach. Najpierw stworzono model impedancyjny przepięcia w wierzy jednopodporowej, a następnie uwzględniono elementy usztywniające. Wykonano przykładowe obliczenia dla wieży pracującej przy napięciu 500 kV.

16

No evidence for a positive response of biomass production to species diversity in an experimental grassland

Ding X., Wang Y., Yu S.

Polish Journal of Ecology

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2012

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Vol. 60, nr 4

667--675

EN

Plant diversity is generally thought to enhance productivity, driven by either (1) chance inclusion of highly productive species in more diverse communities or (2) niche-based resource acquisition with competitive interactions increasing resource use efficiency. Here, we ask whether weeding, as employed in most experiments to date, might contribute to the positive diversity-productivity relationship reported for many grasslands. Using all 82 species from our local pool, we constructed 357 experimental grassland plots (2 × 4 m each), arranged as a completely randomized experiment in an arable field prepared to minimize existing seed bank. The plots were sown to vary species richness (1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35 or 40 species) and were maintained under both ambient conditions and experimental drought. A single monoculture plot was maintained for all 82 species, and each of the other eleven species richness levels was replicated 25 times. Plots were maintained strictly without weeding, and aboveground biomass was measured at 17, 19, 27 and 29 months after the start of this experiment. No single measure of biodiversity was significantly correlated with productivity consistently across all four sampling periods. Furthermore, there were only weak overall effects of six biodiversity variables (the species richness planted, observed, and sampled; Shannon diversity, effective species richness and evenness in the sampled area) on productivity under either precipitation treatment. Regression analysis identified no equation that used a consistent subset of the biodiversity measures as predictors. In view of these transient and insubstantial effects, results from previous experiments that employed weeding treatments are suspect as tests of the hypothesis that biodiversity has positive effects on productivity.

17

Leaf litter decomposition along the temperate - tropical transect (East China) : the influence of stand succession, litter quality and climate

Song X., Jiang H., Peng C., Zhou G., Chang S., Yu S., Ma Y., Peng S., Wei X.

Polish Journal of Ecology

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2012

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Vol. 60, nr 2

265-276

EN

The relationship between litter decomposition and forest succession in addition to the influence of climate variables on the rate of litter decomposition in forest ecosystems are poorly understood. In this study, the effects of forest successional stages, climate, and litter quality on litter decomposition rates were investigated in five sites located in China. The selected sites cover 29 degrees of latitude from 18[degrees]N to 47[degrees]N and spans more than 5,000 km in length along a temperature gradient that transverses across eastern China. This zonal gradient includes five climate zones from temperate to subtropical to tropical zones. Forest types include broad-leaved Korean pine, deciduous broad-leaved, evergreen broad-leaved, monsoon evergreen broad-leaved, and tropical rain forests. The North-South Transect of Eastern China (NSTEC) is one of fifteen international standard transects setup by Global Change and Terrestrial Ecosystems (GCTE). NSTEC is a key component of the International Geosphere-Biosphere Programme (IGBP). The litterbag method was used in this study to determine mass loss and annual decomposition rates of eight tree species (Pinus massoniana Lamb., Cunninghamia lanceolata (Lamb.) Hook., Schima superba Gardn. et Champ., Cinnamomum camphora (L.) Presl., Cyclobalanopsis glauca (Thunb.) Oerst., C. gracilis (Rehd. et Wils.) Cheng et T. Hong, Michelia chapensis Dandy, and Castanopsis eyeri (Champ.) Tutch. through a timeframe starting in May, 2006, and ending in May, 2008. Litterbags 15 x 15 cm and 0.5 x 1.0 mm mesh were filled with 10 g of leaf litter collected from the subtropical forest region and then placed onto the forest floor in triplicate samples for each eight species in all five sites. Three litterbags per species were retrieved from each of the five sites at two month intervals during the two year experimental period. Results suggest that species litter in the climax stage (C. glauca, C. gracilis, and M. chapensis) tended to decompose faster than those in the pioneer stage (P. massoniana and C. lanceolata). Initial phosphorous (P) and nitrogen (N) concentrations of leaf litter were the most critical variables of litter quality in relation to the impact on the rate of litter decomposition. Litter decomposition at different successional stages was found to be directly related to climatic variables such as mean annual precipitation (MAP) and mean annual temperature (MAT). MAP and initial P and N concentrations could therefore be considered good indicators of rates of decomposition.

18

Evaluating the habitat quality of giant panda (Ailuropoda Melanoleuca) using Habitat Suitability Index (HSI)

Jian J., Jiang H., Jiang Z., Zhou G., Yu S., Peng S., Liu S., Liu S., Wang J.

Polish Journal of Ecology

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2012

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Vol. 60, nr 4

827--837

EN

Habitat quality for many wildlife populations has a spatial component related to the arrangement of habitat elements across large geographic areas. With remote sensing and GIS technology, this paper presents an approach to calculate Habitat Suitability Index (HSI) for Giant Pandas to evaluate the habitat quality. In this paper, a buffer of a given distance (30 km or more) to the Giant Panda distribution area estimated in three national surveys (1974, 1989 and 2002), which is located in Sichuan, Gansu and Shanxi provinces in western China, was used as the study area. In order to study different species group’s habitat quality, the study area is divided into five parts: the Qinling mountain systems, located in the southeast in Shanxi province, the Minshan mountain systems, located in the south in Gansu province and northwest in Sichuan province, the Qionglai mountain systems, the Xiangling mountain systems and the Liangshan mountain systems, located in the west of Sichuan province, conforming to the five big Giant Panda species groups. Three physical environmental factors (elevation, slope and aspect), one ecological factor (vegetation distribution) and several human-influence factors (distances to highways, general roads, inhabitants and rural areas) are selected as the influence factors to calculate HSI. Each factor was reclassified by grid-cell (30 × 30 m per cell) to the suitability index scale from 0 to 1 based on habitat affinities before final calculation. After analyzing the HSI values on the most Giant Panda distribution area, 0.0144 was considered as the threshold habitat quality. Then, HSI was calculated for five mountain systems for three periods conforming to three national surveys (1974, 1989 and 2002). Several benefits to the approach can be highlighted. Firstly, HSI can be used as the standard to evaluate the quality of Giant Panda habitat. Secondly, by using HSI maps from 1974, 1989 and 2002, we can see that the Giant Panda habitat was the largest in 1974, and was then reduced much before 1989. However, by 2002, it had recovered to some extent, which conforms to the habitat data from the three national surveys. Thirdly, the habitat changes in the five mountain systems examined in the study are different. Finally, nature reserves play an important role in the protection of Giant Panda habitat; there are more suitable habitats in nature reserves than non-protected areas.

19

State Complexity of Combined Operations with Union, Intersection, Star and Reversal

Gao Y., Yu S

Fundamenta Informaticae

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2012

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Vol. 116, nr 1-4

79-92

EN

In this paper, we study the state complexities of four combined operations: [formula]. The tight bounds for all these combined operations on regular languages are obtained and proved. We show that, as usual, they are different from the mathematical compositions of the state complexities of their individual participating operations.

20

Forecasting carbon budget under climate change and CO2 fertilization for subtropical region in China using Integrated Biosphere Simulator (IBIS) model

Zhu Q., Jiang H., Liu J., Peng C., Fang X., Yu S., Zhou G., Wei X., Ju W.

Polish Journal of Ecology

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2011

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Vol. 59, nr 1

3-23

EN

The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr[^-1] during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr[^-1]. NEP will increase to about 5 Mt C yr[^-1] by the end of the 21st century with the increasing atmospheric CO2concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang.s forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration willhave little contribution to vegetation changes. Simulated NPP shows geographic patterns consistent with temperature to a certain extent, and precipitation is not the limiting factor for forest NPP in the subtropical climate conditions. There is no close relationship between the spatial pattern of NEP and climate condition.