ECMWF模式对陕西2016年春夏季气温预报性能评估     

王丹  王建鹏  潘留杰  何林  程路  戴昌明  胡皓  白庆梅 《气象科技》2018,46(1):92-101

利用2016年春、夏季节陕西99个国家站的气温逐1 h观测数据,对ECMWF高分辨率数值模式对陕西国家站0~72 h逐3 h和78~240 h逐6 h的气温预报性能进行评估。结果表明,陕西大部分地区,气温预报误差≤1 ℃和≤2 ℃的准确率在72 h之前分别为30%~50%和55%~85%,96 h之后分别为10%~30%和25%~55%,夏季的准确率高于春季,20:00起报的准确率略高于08:00起报。随着预报时效的增加,模式的气温预报能力和稳定性波浪式下降,日变化特征明显,23:00至次日11:00时段的预报能力和稳定性好于14:00—20:00时段。模式的气温预报值与观测值有很好的相关性,但是模式和实际观测站的地形高度差异会对气温预报质量产生较大影响。基于气温垂直变率和模式与实际观测站的地形高度差异进行的高度差订正,可以适当提高模式的气温预报水平,文中提出的几种气温预报的高度差订正方法,对陕西大部分地区的气温预报为正订正效果,但还存在一些问题,有待进一步研究。  相似文献   

Observed spatiotemporal variation of three-dimensional structure and heat/salt transport of anticyclonic mesoscale eddy in Northwest Pacific     

Dai  Jun  Wang  Huizan  Zhang  Weimin  An  Yuzhu  Zhang  Ren 《中国海洋湖沼学报》2020,38(6):1654-1675

Journal of Oceanology and Limnology - As in-situ observations are sparse, targeted observations of a specific mesoscale eddy are rare. Therefore, it is difficult to study the three-dimensional...  相似文献   

Can Langmuir Circulations Solve the Problem of Insufficient Upper-Ocean Mixing?     

Huang  Chuanjiang  Qiao  Fangli  Dai  Dejun 《中国海洋大学学报(英文版)》2020,19(4):761-771

Insufficient vertical mixing in the upper ocean during summer is a common problem of oceanic circulation and climate models. The turbulence associated with non-breaking waves is widely believed to effectively solve this problem. In many studies, non-breaking surface wave processes are attributed to the effects of Langmuir circulations(LCs). In the present work, the influences of LCs on the upper-ocean thermal structure are examined by using one-and three-dimensional ocean circulation, as well as climate, models. The results indicated that the effect of vertical mixing enhanced by LCs is limited to the upper ocean. The models evaluated, including those considering LC effects alone and the combined effects of LCs and wave breaking, failed to produce a reasonable summertime thermocline, resulting in a large cold bias in the subsurface layer. Therefore, while they can slightly reduce the biases of mixed layer depths and sea surface temperatures in models, LCs are insufficient to solve the problem of insufficient vertical mixing. Moreover, restriction of non-breaking surface wave-induced processes in LCs may be questionable.  相似文献   

Variations in the potential climatic suitability distribution patterns and grain yields for spring maize in Northeast China under climate change     

Jin Zhao  Xiaoguang Yang  Zhijuan Liu  Shuo Lv  Jing Wang  Shuwei Dai 《Climatic change》2016,134(1-2):29-44

  相似文献   

Seasonal evaluation of evapotranspiration fluxes from MODIS satellite and mesoscale model downscaled global reanalysis datasets     

Prashant K. Srivastava  Dawei Han  Tanvir Islam  George P. Petropoulos  Manika Gupta  Qiang Dai 《Theoretical and Applied Climatology》2016,124(1-2):461-473

  相似文献   

Effects of urban land-use change in East China on the East Asian summer monsoon based on the CAM5.1 model     

Hongyun Ma  Zhihong Jiang  Jie Song  Aiguo Dai  Xiuqun Yang  Fei Huo 《Climate Dynamics》2016,46(9-10):2977-2989

  相似文献   

On the variability of near-bed floc size due to complex interactions between turbulence,SSC, settling velocity,effective density and the fractal dimension of flocs     

Yang Yang  Ya Ping Wang  Chunyan Li  Shu Gao  Benwei Shi  Liang Zhou  Dandan Wang  Gaocong Li  Chen Dai 《Geo-Marine Letters》2016,36(2):135-149

Interactions between turbulence, suspended sediment concentration (SSC), settling velocity, effective density, fractal dimension, and floc size were studied on the tide-dominated, muddy coastal shelf of the southwestern Yellow Sea, China. The measurements were carried out in July 2013 at two sites located in water depths of 21.2 and 22.1 m. Negative correlations were observed between shear rate, SSC, effective density, and mean floc size, which supports the results of previous numerical, experimental, and field studies. A significant positive correlation was observed between near-bed SSC and shear rate, an indication that SSC variations are controlled by turbulence and re-suspension. In addition, significant linear relationships were found between settling velocity and other parameters (floc size, turbulence, SSC, effective density, and fractal dimension) at the two sites, indicating that the controlling factors on settling velocity are spatially variable. Principal component analysis was applied to determine the relative importance of turbulence, flocculation ability, and SSC as controls on floc size in situ. The relative contributions of turbulence, flocculation ability, and SSC to floc size (at both sites) were ~33.0%, 30.3%, and 29.7%, respectively, this being a new field-based quantitative analysis of the controls on floc size. The findings demonstrate that, in nature, flocculation ability affects floc size to the same degree as turbulence and SSC. Therefore, predictions of floc size in coastal marine environments require constraints not only on turbulence and SSC, but also on flocculation ability.  相似文献   

Effect of mariculture on sediment grain size and its potential environmental significance in Sishili Bay,Yellow Sea,China     

Qiao Chen  Dongyan Liu  Yijun Chen  Jiuchuan Wei  Wei Dai 《Environmental Earth Sciences》2016,75(20):1385

  相似文献   

A comparative analysis of fatty acid composition and fucoxanthin content in six <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis> strains from diff erent origins     

吴华莲  李涛  王广华  戴世鲲  何慧  向文洲 《中国海洋湖沼学报》2016,34(2):391-398

Phaeodactylum tricornutum is a potential livestock for the combined production of eicosapentaenoic acid (EPA) and fucoxanthin. In this study, six marine diatom strains identified as P. tricornutum were cultured and their total lipid, fatty acid composition and major photosynthetic pigments determined. It was found that the cell dry weight concentration and mean growth rate ranged between 0.24–0.36 g/L and 0.31–0.33/d, respectively. Among the strains, SCSIO771 presented the highest total lipid content, followed by SCSIO828, and the prominent fatty acids in all strains were C16:0, C16:1, C18:1, and C20:5 (EPA). Polyunsaturated fatty acids, including C16:2, C18:2, and EPA, comprised a significant proportion of the total fatty acids. EPA was markedly high in all strains, with the highest in SCSIO828 at 25.65% of total fatty acids. Fucoxanthin was the most abundant pigment in all strains, with the highest in SCSIO828 as well, at 5.50 mg/g. The collective results suggested that strain SCSIO828 could be considered a good candidate for the concurrent production of EPA and fucoxanthin.  相似文献   

Evaluation of actual evapotranspiration measured by large-scale weighing lysimeters in a humid alpine meadow,northeastern Qinghai-Tibetan Plateau     

Licong Dai  Ruiyu Fu  Xiaowei Guo  Xun Ke  Yangong Du  Fawei Zhang  Yikang Li  Dawen Qian  Huakun Zhou  Guangmin Cao 《水文研究》2021,35(4):e14051

The accurate estimation of evapotranspiration (ET) is essential for assessing water availability and requirements of regional-scale terrestrial ecosystems, and for understanding the hydrological cycle in alpine ecosystems. In this study, two large-scale weighing lysimeters were employed to estimate the magnitude and dynamics of actual evapotranspiration in a humid alpine Kobresia meadow from January 2018 to December 2019 on the northeastern Qinghai-Tibetan Plateau (QTP). The results showed that daily ET_a averaged 2.24 ± 0.10 mm day ⁻¹ throughout the study period, with values of 3.89 ± 0.14 and 0.81 ± 0.06 mm day⁻¹ during the growing season and non-growing season, respectively. The cumulative ET_a during the study period was 937.39 mm, exceeding precipitation (684.20 mm) received at the site during the same period by 37%, suggesting that almost all precipitation in the lysimeters was returned to the atmosphere by evapotranspiration. Furthermore, the cumulative ET_a (805.04 mm) was almost equal to the maximum potential evapotranspiration estimated by the FAO-56 reference evapotranspiration (ET₀) (801.94 mm) during the growing season, but the cumulative ET_a (132.25 mm) was 113.72% less than the minimum equilibrium ET_eq) (282.86 mm) during the non-growing season due to the limited surface moisture in frozen soil. The crop coefficient (K_c) also showed a distinct seasonal pattern, with a monthly average of 1.01 during the growing season. Structural equation model (SEM) and boosted regression tree (BRT) show that net radiation and air temperature were the most important factors affecting daily ET_a during the whole study period and growing season, but that non-growing season ET_a was dominated by soil water content and net radiation. The daily K_c was dominated by net radiation. Furthermore, both ET_a and K_c were also affected by aboveground biomass.  相似文献