Effects of sea ice melt water input on phytoplankton biomass and community structure in the eastern Amundsen Sea

Sea ice melt water and circumpolar deep water(CDW)intrusion have important impacts on the ecosystem of the Amundsen Sea.In this study,samples of nutrients and phytoplankton pigments from nine stations in the eastern Amundsen Sea were collected during the austral summer.Based on in-situ hydrological observations,sea ice density data from satellite remote sensing,and chemical taxonomy calculations,the relationships between environmental factors and phytoplankton biomass and community structure were studied.The results showed that with increasing latitude,the contribution of sea ice melt water(MW%)and the stability of the water body increased,and the depth of the mixed layer(MLD)decreased.The integrated concentration of chlorophyll a(Chl-a)ranged from 21.4 mg·m^(−2) to 148.4 mg·m^(−2)(the average value was 35.7±53.4 mg·m^(−2)).Diatoms(diatoms-A[Fragilariopsis spp.,Chaetoceros spp.,and Proboscia spp.]and diatoms-B[Pseudonitzschia spp.])and Phaeocystis antarctica were the two most widely distributed phytoplankton groups and contributed 32%±16%and 28%±11%,respectively,of the total biomass.The contributions of Dinoflagellates,Chlorophytes,Cryptophytes,the high-iron group of P.antarctica,and Diatom group A were approximately 17%±8%,15%±13%,9%±6%,5%±9%,and 3%±7%,respectively.The area with the highest phytoplankton biomass was located near the ice-edge region,with a short time lag(T_(lag))between sampling and complete sea ice melt and a high MW%,while the area with the second-highest Chl-a concentration was located in the area affected by the upwelling of CDW,with thorough water mixing.Vertically,in the area with a short T_(lag) and a shallow MLD,the phytoplankton biomass and proportion of diatoms decreased rapidly with increasing water depth.In contrast,in the region with a long T_(lag) and limited CDW upwelling,the phytoplankton community was dominated by a relatively constant and high proportion of micro phytoplankton,and the phytoplankton biomass was low and relatively stable vertically.Generally,the phytoplankton community structure and biomass in the study area showed high spatial variation and were sensitive to environmental changes.

Spatial variation of stable isotopes in different waters during melt season in the Laohugou Glacial Catchment, Shule River basin

To evaluate isotopic tracers at natural abundances by providing basic isotope data of the hydrological investigations and assessing the impacts of different factors on the water cycle, a total of 197 water samples were collected from the Laohugou Glacial catchment in the Shule River basin northwestern China during the 2013 ablation seasons and analyzed their H- and O-isotope composition. The results showed that the isotopic composition of precipitation in the Qilianshan Station in the Laohugou Glacial catchment was remarkable variability. Correspondingly, a higher slope of δ180-δD diagram, with an average of 8.74, is obtained based on the precipitation samples collected on the Glacier No.la, mainly attributed to the lower temperature on the glacier surface. Because of percolation and elution, the bottom of the firn the isotopic composition at is nearly steady. The 6180 /altitude gradients for precipitation and melt water were -o.37%o/100 m and -o.34%o/100 m, respectively Exposed to the air and influenced by strong ablation and evaporation, the isotopic values and the 6180 vs 6D diagram of the glacial surface ice show no altitudinal effect, indicating that glacier ice has the similar origins with the firn. The variation of isotopic composition in the melt water, varying from -l0.7‰ to -16.9‰ （8180） and from -61.1%o to -122.1%o （6D） indicates the recharging of snowmelt and glacial ice melt water produced at different altitudes. With a mean value of -13.3‰ for 8180 and -89.7‰ for 8D, the isotopic composition of the stream water is much closer to the melt water, indicating that stream water is mainly recharged by the ablation water. Our results of the stable isotopic compositions in natural water in the Laohugou Glacial catchment indicate the fractionations and the smoothing fluctuations of the stable isotopes during evaporation, infiltration and mixture.

The responses of hydro-environment system in the Second Songhua River Basin to melt water

Based on the continuous monitoring data of hydrology and water quality in the period from 1972 to 1997, the responses of hydro-environment system to melt water in the Second Songhua River basin were derived. Because of melt water, the water quality in the Second Songhua River is good and changes very except that the contents of Hg and Mn in the water are higher. The contribution of melt water to the water fluxes in the Second Songhua River basin is distinct: the water flow in April increases remarkably, reaches the peak in the upper reaches. The pollutant contributions and water pollution indices (WPIs) of the Second Songhua River in April are high in the upper reaches while that in the lower reaches are low. The responses of hydro-environment system to melt water of that basin are affected by content of packed snow and the underlining surface systems.

Accumulation of freshwater in the permanent ice zone of the Canada Basin during summer 2008

A combination of 5180 and salinity data was employed to explore the freshwater balance in the Canada Basin in summer 2008. The Arctic river water and Pacific river water were quantitatively distinguished by using different saline end-members. The fractions of total river water, including the Arctic and Pacific river water, were high in the upper 50 m and decreased with depth as well as increasing latitude. In contrast, the fraction of Pacific river water increased gradually with depth but decreased toward north. The inventory of total river water in the Canada Basin was higher than other arctic seas, indicating that Canada Basin was a main storage region for river water in the Arctic Ocean. The fraction of Arctic river water was higher than Pacific river water in the upper 50 m while the opposite was true below 50 m. As a result, the inventories of Pacific river water were higher than those of Arctic river water, demonstrating that the Pacific inflow through the Bering Strait is the main source of freshwater in the Canada Basin. Both the river water and sea-ice melted water in the permanent ice zone were more abundant than those in the region with sea-ice just melted. The fractions of total river water, Arctic river water, Pacific river water increased northward to the north of 82°N, indicating an additional source of river water in the permanent ice zone of the northern Canada Basin. A possible reason for the extra river water in the permanent ice zone is the lateral advection of shelf waters by the Trans-Polar Drift. The penetration depth of sea-ice melted waters was less than 30 m in the southern Canada Basin, while it extended to 125 m in the northern Canada Basin. The inventory of sea- ice melted water suggested that sea-ice melted waters were also accumulated in the permanent ice zone, attributing to the trap of earlier melted waters in the permanent ice zone via the Beaufort Gyre.

Use of Topographic Map Evidence to Test a Recently Proposed Regional Geomorphology Paradigm: Wind River-Sweetwater River Drainage Divide Area, Central Wyoming, USA

Topographic map evidence from the Wyoming Wind River-Sweetwater River drainage divide area is used to test a recently proposed regional geomorphology paradigm defined by massive south- and southeast-oriented continental ice sheet melt water floods that flowed across the entire Missouri River drainage basin. The new paradigm forces recognition of an ice sheet created and occupied deep “hole” and is fundamentally different from the commonly accepted paradigm in which a pre-glacial north- and northeast-oriented slope would have prevented continental ice sheet melt water from reaching or crossing the Wind River-Sweetwater River drainage divide. Divide crossings (or low points) are identified as places where water once flowed across the drainage divide. Map evidence is interpreted first from the accepted paradigm perspective and second from the new paradigm perspective to determine the simplest explanation. Both paradigm perspectives suggest south-oriented water crossed the drainage divide, although accepted paradigm interpretations do not satisfactorily explain the large number of observed divide crossings and are complicated by the need to bury the Owl Creek and Bridger Mountains to explain why the Wind River now flows in a north direction through Wind River Canyon. New paradigm interpretations explain the large number of divide crossings as diverging and converging channel evidence (as in flood-formed anastomosing channel complexes), Owl Creek and Bridger Mountain uplift to have occurred as south-oriented floodwaters carved Wind River Canyon, and a major flood flow reversal (caused by ice sheet related crustal warping and the opening up of deep “hole” space by ice sheet melting) as being responsible for the Wind River abrupt turn to the north. While this test only addresses topographic map evidence, Occam’s Razor suggests the new paradigm offers what in science should be the preferred Wind River-Sweetwater River drainage divide origin interpretations.

Discussion on possibilities of taking ground ice in permafrost as water sources on the Qinghai-Tibet Plateau during climate warming

Large amounts of ground ice are born with permafrost on the Qinghai-Tibet Plateau.Degradation of permafrost resulted from the climate warming will inevitably lead to melting of ground ice.The water released from the melting ground ice enters hydrologic cycles at various levels,and changes regional hydrologic regimes to various degrees.Due to difficulties in monitoring the perma-frost-degradation-release-water process,direct and reliable evidence is few.The accumulative effect of releasing water,however,is remarkable in the macro-scale hydrologic process.On the basis of the monitoring results of water-levels changes in some lakes on the Qinghai-Tibet Plateau,and combined with the previous results of the hydrologic changing trends at the regional scale,the authors preliminarily discussed the possibilities of the degrading permafrost on the Qinghai-Tibet Plateau as a potential water source during climate warming.

Assessing the global averaged sea-level budget from 2003 to 2010

A global mass balance （Greenland and Antarctica ice sheet mass loss, terrestrial water storage） and differ- ent sea-level components （observed sea-level from satellite altimetry, steric sea-level from Ishii data, and ocean mass from gravity recovery and climate experiment, GRACE） are estimated, in terms of seasonal and interannual variabilities from 2003 to 2010. The results show that a detailed analysis of the GRACE time series over the time period 2003-2010 unambiguously reveals an increase in mass loss from the Greenland ice sheet and Antarctica ice sheet. The mass loss of both ice sheets accelerated at a rate of （392.8±70.0） Gt/a during 2003-2010, which contributed （1.09±0.19） mm/a to the global mean sea-level during this time. The net terrestrial water storage （TWS） trend was negative over the 8 a time span, which gave a small positive contribution of （0.25±0.12） mm/a. The interannual variability of the global mean sea-level was at least part- ly caused by year-to-year variability of land water storage. Estimating GRACE-based ice sheet mass balance and terrestrial water storage by using published estimates for melting glaciers, the results further show that the ocean mass increase since 2003 has resulted half from an enhanced contribution of the polar ice sheets, and half from the combined ice sheet and terrestrial water storage loss. Taking also into account the melt- ing of mountain glaciers （0.41 mm/a） and the small GRACE-based contribution from continental waters （0.25 mm/a）, a total ocean mass contribution of （1.75±0.57） mm/a from 2003 to 2010 is found. Such a value represented 75% of the altimetry-based rate of sea-level rise over that period. The contributions to steric sea-level （i.e., ocean thermal expansion plus salinity effects） are estimated from： （1） the difference between altimetry-based sea-level and ocean mass change and （2） the latest Ishii data. The inferred steric sea-level rate from （1） （1.41 mm/a from 2003 to 2010） did not agree well with the Ishii-based value also estimated here （0.44 mm/a from 2003 to 2010）, but phase. The cause for such a discrepancy is not yet known but may be related to inadequate sampling of in situ ocean temperature and salinity measurements.

Oxygen isotopic composition and its application to the study of tracing oceanographical process in Bering Sea and Chukchi Sea

In this paper, the 18 O distribution of surface water from the central sea areas of the Bering Sea and the Chukchi Sea was studied. The δ 18 O value of surface water from the Bering Sea is averagely -0.5‰; the δ 18 O contents of the Chukchi Sea are distributionally lower in northeast and higher in southwest; the δ 18 O value at the margin of Canadian Basin is -2.8‰, and averagely -0.8‰ in the southern area of the Chukchi Sea. The δ 18 O vertical distribution in some deep water stations from the Chukchi Sea and the Bering Sea is also studied. In the southern margin of Canadian Basin, the δ 18 O value is -2‰ -3‰ for surface layer and rises to 0 at 100 m depth layer. In the Bering Sea, the δ 18 O is about -0.5‰ for surface layer and increases to 0 at the depth of 300 m. The NO tracer can reflect obviously three water masses vertically distributed in the central Bering Sea: the upper Bering water mass, the middle Bering water mass and the deep Pacific water mass. The distributive ranges of NO and temperature for the various water masses are T<7℃, NO>780 μmol/dm 3 and T≥7℃, NO>650 μmol/dm 3 for upper Bering water mass, T<4℃, 550<NO<780 μmol/dm 3 for middle Bering water mass, and T<4℃, 330<NO<550 μmol/dm 3 for deep Pacific water mass. It is found from δ 18 O-S relation diagram and δ 18 O vertical profiles that the δ 18 O is about +0.3‰ from halocline layer till sea bottom. Its isotopic characteristics are the same as the Atlantic water, showing that the sea water comes from the north Atlantic. The freshwater end member of the Chukchi Sea in the survey period is also explored.

高寒区抽水融冰渠道水温沿程衰减规律——以红山嘴水电站为例

抽水融冰技术是解决高寒区引水式电站冬季运行冰害问题的有效措施之一。为研究抽水融冰对电站引水渠道冬季引水的水温控制规律,以红山嘴水电站为例,基于RNGκ-ε模型数值模拟研究结果,从热流量比角度探讨了渠道水温沿程衰减规律,并采用2013年2月和2014年1月原型观测结果进行了验证。结果表明:渠道水温沿程衰减过程可分为骤降段、过渡段和缓降段3部分,各段范围受外界条件控制;衰减曲线呈幂函数分布,相关系数达到98%;对比气温对渠温沿程衰减的影响表明,随着大气温度的降低,渠道水温沿程衰减速度明显加快;-10℃为水温衰减过程变化转折点,当气温高于-10℃时,可以近似认为渠温衰减规律一致,渠温沿程变化主要受到热流量比值影响;低于-10℃时,气温对渠道水温沿程变化影响显著。

高寒区引水渠道抽水融冰不冻长度计算模型及应用

抽水融冰技术是解决高寒地区引水渠道冰害的重要措施,广泛应用于新疆的红山嘴、金沟河和青年水电站以及青海省的香加水电站。该文根据水流热平衡理论,综合考虑水力、热力、气候等条件对不冻长度影响,从理论上得到了不冻长度的计算公式,并用工程实测资料进行了验证,结果表明:引水渠道不冻长度计算结果与原型实测值符合较好,最小误差6.2%,最大误差29.5%;不冻长度与渠道来水流量、井水注入量、井水水温、大气温度、日太阳辐射量成正比,与风速、大气饱和差、日降雪量成反比;其中,渠道来水流量对不冻长度影响较小,井水注入量、大气温度、风速等对不冻长度影响较显著;且保持其他条件不变,井水注入量每增加0.02 m3/s,不冻长度以400 m递增;大气温度每降低5℃,不冻长度减小幅度为16.1%~31.3%;风速从0.5 m/s增加到6.0 m/s,不冻长度减小幅度为4.3%~53.0%;此研究可为解决寒区水电站引水渠道冰灾防治问题提供科学依据。

引水渠道抽水融冰水温沿程变化规律试验研究

在我国严寒地区,为了有效地改善引水式水电站引水渠冰封冰冻现象,可采取抽水融冰方法来保证引水渠道冬季运行畅通,为此对引水渠道抽水融冰水温沿程变化规律进行了试验研究。分别在未注井水、单井注水和双井注水3种情况下,进行了8组不同渠水流量和3组不同井水流量的试验;其中,单井注水试验分别选择了4个不同位置,双井注水的试验分别选择了在6个不同注水位置的组合进行。根据试验结果,分别得到了未注井水、单井注水和双井注水3种情况下,引水渠道水温沿程逐渐减小的变化规律;并结合数据分析,首先得到了未注井水时引水渠道水温沿程变化计算公式,并将计算值和实测值进行了对比,结果表明两者符合较好;在此基础上,重点分析得到了单井注水和双井注水的水温沿程变化计算公式,并分别进行了计算值和实测值的对比分析,结果表明:单井注水和双井注水实测值和计算值最大误差分别为6.25%和5.84%,可以用于实际工程水温沿程变化计算。

高寒区引水渠道水温变化规律的试验研究

在高寒地区,抽水融冰是引水式水电站冬季运行除冰害的一种有效措施。为了更好地研究抽水融冰过程中引水渠道水温变化规律,本研究结合新疆红山嘴水电站工程的实际应用,对抽水融冰过程进行了室外水槽模拟试验。试验在实际大气温度下分别分析了相同渠水流量、不同井水流量和相同井水流量、不同渠水流量条件下,引水渠水温沿程的变化规律,结果表明:各种加井水条件下的渠水水温都比不加井水时要高,渠水水温先升高后降低,并有一峰值,峰值出现在加水点4-8 m处,说明冬季抽取地下水注入引水渠的方法是可行的;当渠水流量确定的情况下,随着井水流量的增大,渠水温度升高幅度也显著增大,增幅明显,从井水流量0.06 L/s时的0.5-1.25℃增大到井水流量0.14 L/s时的0.35-0.77℃,增幅为0.15-0.48℃左右;当井水流量确定的情况下,随着渠水流量的增大,渠水水温升高幅度减小,从渠水流量1.5 L/s时升高的0.77-1.9℃减小到渠水流量7.5 L/s时升高的0.26-0.45℃,减小幅度为0.51-1.45℃。该试验结果可为抽水融冰运行机理提供科学依据并为实际工程提供借鉴意义。

红山嘴水电站抽水融冰原型试验及不冻长度计算

主要介绍了新疆红山嘴水电站应用抽水融冰技术解决长期困扰水电站运行的冰害问题,给出了高寒区引水渠道冬季运行抽水融冰基本原理。根据原型观测结果,分析得出了抽水后渠道水温的沿程变化规律。参照经验公式对不冻长度进行了计算,并将结果与2级引水渠上布置的融冰井间距作了对比,为抽水融冰井群优化布置等相关内容研究奠定了基础。

多功能空调冰蓄冷实验装置的研制及应用

该实验装置集成了冰蓄冷系统及空气源/水源热泵冷热水系统形式,可完成三种蓄冰/融冰性能实验及空气源/水源热泵冷热水机组供冷、供热实验。介绍了实验装置的构成和功能,以及实验参数的测量和实验工况的控制。初步实验结果表明,实验台工况控制稳定可靠,参数测量精度较高。

三江平原白浆土水分状况的研究——白浆土水分周年动态及其对农业生产的影响(二)

为了说明土壤供水与作物需水之间的关系，将观测年度4-9月土壤有效水量(土壤含水量与萎蔫系数之差)和易效水量（土壤含水量与毛管联系断裂水量之差）列于表4。作物各生育期的蒸散量（叶面蒸腾与土面蒸发之和）是难以测定的。这里我们采用布莱尼法计算作物耗水量，权资参考。布莱尼——克利德尔公式：

高寒区引水渠道抽水融冰水温变化过程模拟

抽水融冰技术能解决中国西北等高寒地区引水式水电站引水渠冰害。该文以新疆红山嘴电站引水渠道为研究对象,对引水渠道抽水融冰水温变化过程进行数值模拟。通过对模拟结果与原型观测结果对比研究,验证数值模型的可靠性。最后分别模拟分析井水流量、渠道流量、井水温度、渠道水温、流量和温度同时变化时,引水渠道水温沿程变化规律。结果表明：1）井水流量和井水温度变化与混合后水温成正比,井水流量越大,水温越高,渠道增温效果越明显;2）渠道流量变化与混合后水温成反比,渠道流量越大,井水的增温效果越不明显;3）渠道水温与混合后水温成正比,渠道水温越低,混合后水温也越低;4）渠道引水温度降低为原来0.25倍,同时井水流量增大至原来4倍,混合后水温比降低渠水温度时高0.14-1.43℃,在实际工程中,增加井水流量是抽水融冰最有效的方法。研究为寒区引水渠道冰害的防治提供科学依据。

高寒区多口融冰井引水渠道水温变化三维模拟及井群优化布置

为探讨抽水融冰技术解决严寒地区渠道冰害的效果,以新疆玛纳斯河流域红山嘴二级电站引水渠道为研究对象,对多口融冰井同时运行条件下引水渠道水温变化过程进行三维模拟,其模拟结果和原型观测结果平均相对误差为4.61%,验证了数值模拟的可靠性。在此基础上,通过改变井水流量、井前渠水流量和水温、外界大气温度等条件,对混合水温沿程变化过程进行了模拟。结果表明:1)仅将井水流量变为原来的50%和1.5倍时,井水注入量与混合水温成正比,且对混合水温的影响较大;2)仅将井前渠道水温分别降低和升高0.2和0.4℃时,井前渠道水温与混合水温成正比,且对混合水温的影响也较大,因此增大井水流量或者合理布置井群是抽水融冰最有效的方法;3)根据井前渠道水温为0.1℃,井前渠水流量分别为10、15、20和25 m^3/s,大气温度分别为–5、–10、–20和–30℃的模拟结果,得到了各井的不冻长度值,且随着井前渠道流量增大和外界大气温度降低,融冰井的不冻长度均随之减小,最后给出了在不同井前渠道流量和不同气温条件下融冰井的不冻长度和井的布置桩号等合理优化布置方案,此研究为解决寒区水电站引水渠道冰灾防治问题提供科学依据。

高寒区引水渠道抽水融冰原型试验及分析

在我国新疆、西藏等西部高寒地区,抽水融冰是解决该地区引水式电站冬季运行冰害的理想措施。本文在对引水渠道冬季运行冰害形成过程及影响分析的基础上,结合新疆玛纳斯河流域红山嘴水电站应用抽水融冰情况,介绍了高寒区引水渠道冬季运行抽水融冰基本原理,并根据抽水融冰原型试验结果分析了抽水融冰的运行效果,给出了渠道水与井水混合后的温度变化过程以及渠道水温沿程变化规律等,进一步论证了抽水融冰理论的正确性和可行性。

Variation of upper-ocean heat content in the Canada Basin in summers of 2003 and 2008

Conductivity, temperature, and depth data collected during the summers of 2003 and 2008 were used to study upper-ocean （top 200 m） heat content in the Canada Basin. The variation of heat content with depth, heat content differences between the summers, principal driving factors, and horizontal spatial scale differences were analyzed. A catastrophic reduction of sea ice cover in the Canada Basin was evident in 2008 by comparison with 2003, suggesting that more solar radiation was absorbed in the upper ocean during the summer of 2008. The sea ice reduction produced more freshwater in the upper ocean. Thus, seawater properties changed. The study shows that the huge reduction of sea ice would result in two changes-widespread warming of the upper ocean, and the depth of Pacific inflow water in the basin increased substantially. Near-surface temperature maximum （NSTM） water was also analyzed as an indicator of Arctic Ocean warming.

重庆江北城江水源热泵区域供冷供热系统设计

介绍了重庆市江北城中央商务区(CBD)的江水源热泵集中供冷供热项目能源站的系统设计。计算了该能源站的空调冷热负荷,详细介绍了机房布置、自控设计、冰槽做法及对水环境的影响。该工程将冰蓄冷与热泵系统结合,同时实现了区域集中供冷供热,并采用了江水直接冷却技术。经测评,该系统相对传统的供冷供热系统,夏季节约费用993.3万元,冬季节约费用909.4万元,具有良好的经济性。