西北冰洋陆坡区极北哲水蚤种群快速补充研究     

徐志强  张光涛  孙松 《海洋学报(英文版)》2018,37(5):87-95

在北冰洋的高纬度海区，陆坡—海盆之间的交换对极北哲水蚤（Calanus hyperboreus）的种群补充具有非常重要的意义。为了研究极北哲水蚤在西北冰洋种群补充的地理差异，我们利用2003年夏季所采集的样品，分析了该物种的丰度、种群结构和体长分布。从总丰度的地理分布来看，极北哲水蚤主要分布在楚科奇海与楚科奇深海平原之间的陆坡区（CS-slope），而在水深较浅的楚科奇海并没有记录。在CS-slope区域，极北哲水蚤的总丰度在1 110.0—5 815.0个/m³之间，而其他海区的总丰度在40.0—950.0个/m³之间。从不同的发育期分布上来看，早期幼体（CI-CIV）在CS-slope区域占优势，而CV期幼体和成体在深水海盆区占优势。从体长的地理分布上来看，差异最为明显的是CⅢ期幼体，其在CS-slope区域的前体长在2.48—2.61 mm之间，而在其他海区的前体长在2.16—2.37 mm之间。与环境因子相关性的分析结果显示，早期幼体（CI-CIV）的丰度与叶绿素a的浓度呈正相关关系，而CV期幼体和成体却与叶绿素a的浓度呈负相关关系。我们的结果表明，极北哲水蚤可以通过加快第一个生长季节的发育速度而受益于初级生产力的增加，并且高生产力的CS-slope区域是陆坡-海盆之间种群补充的潜在来源。  相似文献   

The impacts of climate change on local hydrology and low flow frequency in the Geum River Basin,Korea     

Jae H. Ryu  Joo Heon Lee  Sangman Jeong  Seon K. Park  Kyuha Han 《水文研究》2011,25(22):3437-3447

The climate sensitive analysis of potential climate change on streamflow has been conducted using a hydrologic model to identify hydrologic variability associated with climate scenarios as a function of perturbed climatic variables (e.g. carbon dioxide, temperature, and precipitation). The interannual variation of water resources availability as well as low flow frequency driven by monsoonal time shifts have been investigated to evaluate the likelihood of droughts in a changing climate. The results show that the timing shift of the monsoon window associated with future climate scenarios clearly affect annual water yield change of ? 12 and ? 8% corresponding to 1‐month earlier and 1‐month later monsoon windows, respectively. Also, a more severe low flow condition has been predicted at 0·03 m³/s as opposed to the historic 7Q10 flow of 1·54 m³/s given at extreme climate scenarios. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Fifty years of runoff response to conversion of old-growth forest to planted forest in the H. J. Andrews Forest,Oregon, USA     

Emily A. Crampe  Catalina Segura  Julia A. Jones 《水文研究》2021,35(5):e14168

Long-term watershed experiments provide the opportunity to understand forest hydrology responses to past logging, road construction, forest regrowth, and their interactions with climate and geomorphic processes such as road-related landslides. We examined a 50-year record from paired-watershed experiments in the H. J. Andrews Experimental Forest, Oregon, USA in which 125 to 450-year-old conifer forests were harvested in the 1960s and 1970s and converted to planted conifer forests. We evaluated how quickflow and delayed flow for 1222 events in treated and reference watersheds changed by season after clearcutting and road construction, including 50 years of growth of planted forest, major floods, and multi-decade reductions in snowpack. Quickflow runoff early in the water year (fall) increased by up to +99% in the first decade, declining to below pre-harvest levels (−1% to −15%) by the third to fifth decade after clearcutting. Fall delayed flow responded more dramatically than quickflow and fell below pre-treatment levels in all watersheds by the fifth decade, consistent with increased transpiration in the planted forests. Quickflow increased less (+12% to 70%) during the winter and spring but remained higher than pre-treatment levels throughout the fourth or fifth decade, potentially impacted by post-harvest burning, roads, and landslides. Quickflow remained high throughout the 50-year period of study, and much higher than delayed flow in the last two decades in a watershed in which road-related changes in flow routing and debris flows after the flood of record increased network connectivity. A long-term decline in regional snowpack was not clearly associated with responses of treated vs. reference watersheds. Hydrologic processes altered by harvest of old-growth conifer forest more than 50 years ago (transpiration, interception, snowmelt, and flow routing) continued to modify streamflow, with no clear evidence of hydrologic recovery. These findings underscore the importance of continued long-term watershed experiments.  相似文献   

全球气候模式中赤道东太平洋海表温度的季节循环：从CMIP5到CMIP6     

宋振亚  刘海龙  陈幸荣 《海洋学报(英文版)》2020,39(7):50-60

The sea surface temperature(SST) seasonal cycle in the eastern equatorial Pacific(EEP) plays an important role in the El Ni?o–Southern Oscillation(ENSO) phenomenon. However, the reasonable simulation of SST seasonal cycle in the EEP is still a challenge for climate models. In this paper, we evaluated the performance of 17 CMIP6 climate models in simulating the seasonal cycle in the EEP and compared them with 43 CMIP5 climate models. In general, only CESM2 and SAM0-UNICON are able to successfully capture the annual mean SST characteristics,and the results showed that CMIP6 models have no fundamental improvement in the model annual mean bias.For the seasonal cycle, 14 out of 17 climate models are able to represent the major characteristics of the observed SST annual evolution. In spring, 12 models capture the 1–2 months leading the eastern equatorial Pacific region 1(EP1; 5°S–5°N, 110°–85°W) against the eastern equatorial Pacific region 2(EP2; 5°S–5°N, 140°–110°W). In autumn,only two models, GISS-E2-G and SAM0-UNICON, correctly show that the EP1 and EP2 SSTs vary in phase. For the CMIP6 MME SST simulation in EP1, both the cold bias along the equator in the warm phase and the warm bias in the cold phase lead to a weaker annual SST cycle in the CGCMs, which is similar to the CMIP5 results. However,both the seasonal cold bias and warm bias are considerably decreased for CMIP6, which leads the annual SST cycle to more closely reflect the observation. For the CMIP6 MME SST simulation in EP2, the amplitude is similar to the observed value due to the quasi-constant cold bias throughout the year, although the cold bias is clearly improved after August compared with CMIP5 models. Overall, although SAM0-UNICON successfully captured the seasonal cycle characteristics in the EEP and the improvement from CMIP5 to CMIP6 in simulating EEP SST is clear, the fundamental climate models simulated biases still exist.  相似文献   

Addressing uncertainty in reflectivity‐rainfall relations in mountain watersheds during summer convection          下载免费PDF全文

Hernan A. Moreno  Enrique R. Vivoni  David J. Gochis 《水文研究》2014,28(3):688-704

The use of precipitation estimates from weather radar reflectivity has become widespread in hydrologic predictions. However, uncertainty remains in the use of the nonlinear reflectivity–rainfall (Z‐R) relation, in particular for mountainous regions where ground validation stations are often lacking, land surface data sets are inaccurate and the spatial variability in many features is high. In this study, we assess the propagation of rainfall errors introduced by different Z‐R relations on distributed hydrologic model performance for four mountain basins in the Colorado Front Range. To do so, we compare spatially integrated and distributed rainfall and runoff metrics at seasonal and event time scales during the warm season when convective storms dominate. Results reveal that the basin simulations are quite sensitive to the uncertainties introduced by the Z‐R relation in terms of streamflow, runoff mechanisms and the water balance components. The propagation of rainfall errors into basin responses follows power law relationships that link streamflow uncertainty to the precipitation errors and streamflow magnitude. Overall, different Z‐R relations preserve the spatial distribution of rainfall relative to a reference case, but not the precipitation magnitude, thus leading to large changes in streamflow amounts and runoff spatial patterns at seasonal and event scales. Furthermore, streamflow errors from the Z‐R relation follow a typical pattern that varies with catchment scale where higher uncertainties exist for intermediate‐sized basins. The relatively high error values introduced by two operational Z‐R relations (WSR‐57 and NEXRAD) in terms of the streamflow response indicate that site‐specific Z‐R relations are desirable in the complex terrain region, particularly in light of other uncertainties in the modelling process, such as model parameter values and initial conditions. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

地表温度日变化模型偏差系数解算的地表温度降尺度     

王爱辉  杨英宝  潘鑫  章勇  胡解君德 《遥感学报》2021,25(8):1735-1748

地表温度LST（Land Surface Temperature）是全球气候变化研究的关键参数,遥感是获取全球和区域尺度地表温度的一种切实可行手段,但现有的单一传感器无法提供高时空分辨率的LST数据,限制了遥感地表温度数据的深入广泛应用。现有的降尺度方法难以生成无缝高时空分辨率的地表温度数据,且降尺度效果易受高空间分辨率LST数据缺失及有效时刻分布影响。本文提出了一种基于地表温度日变化模型DTC（Diurnal Temperature Cycle）偏差系数解算的地表温度降尺度方法,采用FY-4A、MODIS和Landsat 8的LST数据生成晴空及多云条件下逐小时100 m的无缝LST数据。方法主要包含4部分：（1）利用空值重建方法获取无缝的FY-4A的LST数据;（2）建立FY-4A LST数据的DTC模型;（3）采用时空融合模型对MODIS的LST数据进行空间降尺度;（4）解算DTC模型偏差系数,获取逐小时100 m分辨率的无缝LST数据。实验结果表明,本文提出的方法具有较高的降尺度精度,可获得晴空及多云条件下无缝高时空地表温度数据,且高空间分辨率的地表温度数据缺失和有效时刻分布对本文方法降尺度结果影响较小。  相似文献   

长江流域陆地水储量与多源水文数据对比分析   总被引：1，自引：0，他引：1       下载免费PDF全文

王文  王鹏  崔巍 《水科学进展》2015,26(6):759-768

从趋势性、滞后性及相关性三方面,对2002—2013年间GRACE重力卫星反演的长江上游与中游陆地水储量与模型模拟土壤含水量、实测降水和实测径流数据进行了对比分析,并从干旱强度及发展时间两方面评估了标准化陆地水储量指数SWSI、标准化降水指数SPI、标准化径流指数SRI和标准化土壤含水量指数SSMI对区域性干旱的表征能力.结果表明:长江上游地区陆地水储量与降水、径流和土壤水蓄量均无显著变化,而中游地区陆地水储量则与水库蓄量同样具有显著性增加,反映人类活动对中游地区陆地水储量变化有很大影响;各指标指示的各等级干旱月份数量基本相当,但各指标反映的特旱具体月份有较大差别,基于GRACE数据构建的SWSI指标对特大干旱的指示性不好;对比各指标对上游与中游地区干旱事件发展时间,体现出水文干旱、农业干旱对气象干旱存在一定的迟滞关系.  相似文献   

1956—2010年中国水热季节性特征分析          下载免费PDF全文

章诞武  丛振涛  倪广恒 《水科学进展》2015,26(4):466-472

流域水文平衡不仅决定于降水和潜在蒸散发总量,而且还受到其年内季节性变化特征的影响。收集1956—2010年中国743个国家级气象站逐日气候资料,采用FAO-Penman公式计算潜在蒸散发量,插值计算10 km网格日降水和潜在蒸发,进行水热季节性特征的变化分析。结果表明,82.8%的区域潜在蒸散发量均值有下降趋势,但减少量不大,同时其年内季节性特征没有显著变化。表征降水年内波动振幅的季节性指数在全国范围均有显著下降趋势,且北方流域更为明显,变化率最大的西北诸河达到6.4%/10 a;峰值时间和雨季长度则变化不显著。这种水热季节性的变化被认为会导致流域径流的减少,在今后中国径流变化的归因研究中,应该考虑降水季节性变化的贡献。  相似文献   

辽东桓仁西部小岭旋回火山岩地球化学特征及成因          下载免费PDF全文

杨占兴  骆念岗 《地质找矿论丛》2015,30(4):567-574

小岭旋回火山岩是辽东中生代火山岩的重要组成部分,主要岩性有安山岩、英安岩以及流纹质火山碎屑岩,属钾质钙碱性系列。其地球化学特征显示,火山岩总体具有高K、Na,低Al、Fe、Ca的特点。其中,火山熔岩具有富集Nb、Th、Hf、Zn,相对亏损Cs、Li、Sr的特点;火山碎屑岩普遍具贫Sr、V、Cu、Li,富含Hf的特点。火山岩总体为稀土富集型,安山岩及安山质火山碎屑岩,略显Eu正异常;流纹岩及流纹质火山碎屑岩具明显Eu负异常。火山岩成岩物质来源于地壳,成因以部分熔融为主,部分岩石显示具陆壳混染特点。火山岩形成动力来自于太平洋板块向古欧亚板块的俯冲,形成于早期拉张—晚期挤压的构造背景,具有板内活动带火山岩的特征。  相似文献   

生命周期视角下建成环境对居民迁居强度的影响——基于武汉市多源数据分析     

刘华  周田原  张贵科  刘学军  邓韶辉 《地理科学进展》2023,42(1):66-78

随着中国城镇住房制度改革的推行,城市内迁居行为日趋频繁。洞悉不同年龄段居民迁居内在驱动力,能为城市居住环境规划与建设改善提供依据。论文利用2019年与2021年武汉市手机信令等多源数据,以生命周期理论为研究视角,识别武汉市四环内不同年龄段居民交通小区迁居强度,并提出建成环境因子特性与迁居强度关系模型,探讨居民生活圈内各建成环境因子对多年龄段居民迁居影响的特性差异。研究发现：(1)不同年龄居民的迁入与迁出强度在不同城市区位上存在分异,19～39岁居民相较于40岁以上居民迁居更频繁;总体呈现内环线的交通小区迁入与迁出强度表征偏高,且均大于外环线的交通小区。(2)公共服务设施、交通便利度和居住环境维度内相关指标是影响居民迁居决策的重要因素,由于不同年龄段居民居住需求不同,部分变量因子在不同年龄段下特性分异明显。考虑到各年龄段居民迁居强度及因子特性不一,相关规划决策需采取差异化的建成环境改善措施,科学引导不同年龄居民迁居,优化城市人口分布。  相似文献