西北太平洋海洋温度锋生与锋消机制的初步研究

海洋锋面区域对气候变化以及海气耦合作用的影响非常显著,通过分析其形成机制,可以帮助进一步了解海洋与大气的相互作用过程以及其物理过程。利用Argo数据、NCEP/NCAR再分析数据和遥感风场数据对西北太平洋的混合层温度与温度锋面的变化机制进行了研究。基于海洋混合层的热量收支模型,发现在北太平洋区域的海洋混合层温度主要受到净热通量控制,同时还存在一个季节变化明显的温度锋面。9~2月为温度锋面加强时期,3~4月温度锋面变化不明显,而5~8月温度锋面则迅速减弱。根据研究,该温度锋面的加强与减弱主要是由于净热通量的南北差异造成的,而在净热通量中则以短波辐射通量与潜热通量为主要影响因子。     

Mechanism for the Formation of Temperature Anomalies in the Upper Layer of the North Atlantic

ORA-S3 oceanological reanalysis data for 1959–2011 is applied to analyze the role different factors play in forming advective heat transfer anomalies on an interannual–decadal scale in the upper mixed layer of the North Atlantic. Regions are revealed in which horizontal heat advection anomalies are determined by variations in current intensity, temperature gradients, and their joint influence. It is demonstrated that the contribution of different mechanisms responsible for advective heat transfer anomalies in the upper mixed layer to the total anomalies of advective origin varies fundamentally from one current to another in the North Atlantic. In the Gulf Stream area (after it separates from the continental slope), horizontal heat advection anomalies in the upper mixed layer result mainly from fluctuations in current intensity, while in the Caribbean Current and the Gulf Stream area (until its separation), they result from variations in the horizontal temperature gradients in the upper mixed layer. In the Labrador Current, both of these mechanisms have the same sign and approximately the same absolute values. In the East Greenland Current, they compensate each other. The contribution of anomalies in horizontal temperature gradients transferred by anomalous currents to the formation of heat transfer anomalies in the upper layer of the North Atlantic are, on the whole, relatively small throughout the water area. The areas of the North Atlantic and West Greenland currents are exceptions.     

东海西北部中层冷水垂直热结构数值预报方法研究 Ⅱ.三维数值预报模式

根据含中层冷水海洋垂直热结构的特征,将其分为4层,并考虑来自海面的热力和动力强迫因子、水层界面剪切应力和卷挟热交换、热平流、混合及地形影响等条件下,从原始动量、连续方程组及热传导方程出发,对整个海洋和各水层分别进行垂向积分,导出相应的描述风生界面起伏、各水层平均流场和温度场的闭合方程组.当解得各水层的平均温度场T_k(k=1,2,3,4)后,根据Tk与对应水层界面特征温度间的关系获得后者,最后通过水温剖面表达式获得含中层冷水海洋的三维热结构.为了检验本模式的功能,以时效为5d试报了5月15日研究海域的三维热结构,并将试报结果与实测值进行了比较.结果表明,试报水温的均绝误差为025℃,效果令人满意.     

Evaluation of the heat balance constituents of the upper mixed layer in the North Atlantic

Different physical mechanisms which cause interannual and interdecadal temperature anomalies in the upper mixed layer (UML) of the North Atlantic are investigated using the data of ORA-S3 reanalysis for the period of 1959–2011. It is shown that the annual mean heat budget in UML is mainly caused by the balance between advective heat transfer and horizontal turbulent mixing (estimated as a residual term in the equation of thermal balance). The local UML temperature change and contribution from the heat fluxes on the lower boundary of the UML to the heat budget of the upper layer are insignificant for the time scale under consideration. The contribution of the heat fluxes on the upper UML boundary to the low-frequency variability of the upper layer temperature in the whole North Atlantic area is substantially less than 30%. Areas like the northwestern part of the Northern Subtropical Anticyclonic Gyre (NSAG), where their contribution exceeds 30–60%, are exceptions. The typical time scales of advective heat transfer variability are revealed. In the NSAG area, an interannual variability associated with the North Atlantic Oscillation dominates, while in the North Atlantic subpolar gyre, an interdecadal variability of advective transfers with periods of more than 30 years prevails.     

Research on the Propagation Acting of the Equatorial Planetary Waves on the Western Equatorial Pacific Warm Pool Heat

1 IntroductionIn the Equatorial Pacific, due to the difference between the atmospheric circulation and air-sea interaction, the near-surface seawater heat structure in the eastern and western Pacific presents two ℃obviously different characteristics: warm pool ( > 28 ) in the western equatorial Pacific and cold ℃tongue ( < 24 ) in the eastern equatorial Pacific. The water bodies of these two heat structures would give rise to change in spatial distribution under the action of the equato…     

基于水下滑翔机观测数据的西北太平洋混合层特征研究

基于水下滑翔机在2019年8至10月观测到的温盐资料,本研究分析了西北太平洋混合层总体的变化情况,并探讨了混合层异常变化的原因。结果表明,混合层温度总体上呈现随季节转换逐渐降低的趋势,混合层深度总体上呈现随季节转换逐渐增大的趋势。进一步的相关性分析得出,该海域混合层温度、混合层深度的变化特征主要是由外部大气强迫场(海面风场和净热通量)所决定的。水下滑翔机还观测到了混合层温度异常降低、混合层深度异常变浅的现象。通过计算混合层热收支发现,垂向夹卷作用是海洋混合层内温度降低和混合层深度变浅的主要原因。通过进一步计算研究海域冷涡的上升速度与海水垂向夹卷速度的变化情况,并结合卫星遥感资料,得出海洋的中尺度涡旋活动主导了混合层异常现象的发生。     

Contributions of shortwave radiation to the formation of temperature inversions in the Bay of Bengal and eastern equatorial Indian Ocean: A modeling approach

Variations in incoming shortwave radiation influence the net surface heat flux, contributing to the formation of a temperature inversion. The effects of shortwave radiation on the temperature inversions in the Bay of Bengal and eastern equatorial Indian Ocean have never been investigated. Thus, a high-resolution (horizontal resolution of 0.07°×0.07° with 50 vertical layers) Regional Ocean Modeling System (ROMS) model is utilized to quantify the contributions of shortwave radiation to the temperature inversions in the study domain. Analyses of the mixed layer heat and salt budgets are performed, and different model simulations are compared. The model results suggest that a 30% change in shortwave radiation can change approximately 3% of the temperature inversion area in the Bay of Bengal. Low shortwave radiation reduces the net surface heat flux and cools the mixed layer substantially; it also reduces the evaporation rate, causing less evaporative water vapor losses from the ocean than the typical situation, and ultimately enhances haline stratification. Thus, the rudimentary outcome of this research is that a decrease in shortwave radiation produces more temperature inversion in the study region, which is primarily driven by the net surface cooling and supported by the intensive haline stratification. Moreover, low shortwave radiation eventually intensifies the temperature inversion layer by thickening the barrier layer. This study could be an important reference for predicting how the Indian Ocean climate will respond to future changes in shortwave radiation.     

Thermal advection in the tropical Atlantic upper layer

This paper focuses on the heat advection calculated for the tropical Atlantic upper mixed layer and a 0–200 m layer, using two different methods, specifically, (i) from the change in the heat content and the external heat balances and (ii) on the basis of the flows and horizontal seawater temperature gradients prescribed. Thermal advection in the upper mixed layer, in terms of its geographical distribution and the order of magnitude, coincides with that of the 0–200 m layer. This allows the deduction that basically the heat in the tropical Atlantic is transferred within the upper mixed layer. Seasonal variations of the heat advection prove to be appreciable; the annual course is well approximated by two principal waves, one having annual and the other semi-annual cyclicity, with the annual wave being predominant. Both waves reproduce 90% of the dispersion of monthly thermal advection.Translated by Vladimir A. Puchkin.     

Spatiotemporal variation and mechanisms of temperature inversion in the Bay of Bengal and the eastern equatorial Indian Ocean

In the northern Bay of Bengal, the existence of intense temperature inversion during winter is a widely accepted phenomenon. However, occurrences of temperature inversion during other seasons and the spatial distribution within and adjacent to the Bay of Bengal are not well understood. In this study, a higher resolution spatiotemporal variation of temperature inversion and its mechanisms are examined with mixed layer heat and salt budget analysis utilizing long-term Argo（2004 to 2020） and RAMA（2...     

20世纪90年代后期南海上层海温变化趋势的转折

In this paper, the interdecadal variability of upper-ocean temperature in the South China Sea(SCS) is investigated based on several objectively analyzed data sets and two reanalysis data sets. The trends of the SCS sea surface temperature(SST) have changed from warming to cooling since the late 1990 s. A heat budget analysis suggests that the warming of the surface mixed layer during 1984–1999 is primarily attributed to the horizontal heat advection and the decrease of upward long wave radiation, with the net surface heat flux playing a damping role due to the increase of upward latent and sensible heat fluxes. On the other hand, the cooling of the surface mixed layer during 2000–2009 is broadly controlled by net surface heat flux, with the radiation flux playing the dominant role. A possible mechanism is explored that the variation of a sea level pressure(SLP) over the North Pacific Ocean may change the prevailing winds over the SCS, which contributes to the change of the SST in the SCS through the horizontal heat advection and heat fluxes.     

Temporal variations of the winter mixed layer south of the Kuroshio Extension

A monthly mean time series of the temperature profile in the recirculation gyre south of the Kuroshio Extension has been produced for the period 1971–2007 to examine temporal variations of the winter mixed layer. The winter mixed layer depth (MLD) shows both interannual and decadal variations and is significantly correlated with variation of the mean net surface heat flux in late autumn to early winter. There is also a close relation with the strength of pre-existing subsurface stratification, measured as vertical temperature gradients in the preceding summer. Linear multiple regression analysis shows that a significant fraction of the variations in the winter MLD is explained by the surface heat flux and the strength of the stratification. The contribution of the two factors is comparable.     

海洋上层温度结构特征的参数模式

本文根据Ｃ．Ａ．等（１９６３。１９６５）提出的海洋上层温度结构特征的无因次普遍函数，利用１９５７～１９６４年暖半年渤海、黄海、东海１５９个站次连续站的资料和作者（１９８３）提出的海面热量平衡的简易计算公式计算海面的热量收支，建立了海洋上均匀层厚度、温跃层强度和跃层下界深度的半经验半理论模式。该模式反映了形成海洋上层温度结构特征的主要因子及其作用，同时避开了一般理论模式中的起算点和目前难以获得的物理海洋学参数，而可以直接利用表面水温、气温和风速进行海洋上层温度特征的计算。     

Supply of Heat by Tsushima Warm Current in the East Sea (Japan Sea)

A significant surface net heat loss appears around the Kuroshio and the Tsushima Warm Current regions. The area where the surface heat loss occurs should require heat to be supplied by the current to maintain the long-term annual heat balance. Oceanic heat advection in these regions plays an important role in the heat budget. The spatial distribution of the heat supply by the Tsushima Warm Current near the surface was examined by calculating the horizontal heat supply in the surface layer of the East Sea (the Japan Sea) (ESJS), directly from historical sea surface temperature and current data. We have also found a simple estimation of the effective vertical scale of heat supply by the current to compensate net heat loss using the heat supplied by the current in the surface 10 m layer. The heat supplied by the current for the annual heat balance was large in the Korea/Tsushima Strait and along the Japanese Coast, and was small in the northwestern part of the ESJS. The amount of heat supplied by the current was large in the northwestern part and small in the south-eastern part of the ESJS. These features suggest that the heat supplied by the Tsushima Warm Current is restricted to near the surface around the northeastern part and extends to a deeper layer around the southeastern part of the ESJS. This revised version was published online in August 2006 with corrections to the Cover Date.     

Countergradient heat transfer in the atmospheric boundary layer over a rough surface

The nonlocality of the mechanism of turbulent heat transfer in the atmospheric boundary layer over a rough surface manifests itself in the form of bounded areas of countergradient heat transfer, which are diagnosed from analysis of balance items in the transport equation for the variance of temperature fluctuations and from calculation of the coefficients of turbulent momentum and heat transfer invoking the model of “gradient diffusion.” It is shown that countergradient heat transfer in local regions is caused by turbulent diffusion or by the term of the divergence of triple correlation in the balance equation for the temperature variance.     

ENSO事件非对称性成因研究

利用NCEP、SODA等再分析资料,对东太平洋上层海洋的热量收支进行了计算,研究了产生ENSO冷暖事件强度非对称的可能原因。对海表温度异常(SSTA)的分析发现,在东太平洋SSTA存在明显的正偏,即El Nio事件中正异常的幅度大于La Nia事件中负异常的幅度,体现出ENSO事件的非对称性。通过对上层海洋热量收支的计算发现,造成ENSO事件非对称性的可能原因有3个:(1) 非线性温度平流,水平非线性温度平流在ENSO冷暖事件中均为正值,因此增强El Nio事件而减弱La Nia事件;(2) 次表层温度异常对温跃层深度异常的非线性响应,由于东太平洋温度剖面的特性,使得次表层温度异常对El Nio期间正的温跃层深度变化更为敏感,造成次表层温度异常幅度在El Nio期间比La Nia期间大,从而通过－wT′_z项引起上层海温的非对称性;(3) 赤道太平洋的纬向风异常的正偏:由于赤道太平洋存在较强的纬向西风,导致东太平洋温跃层深度异常正偏,进而造成次表层温度异常的非对称－wT′_z,并通过项影响上层海温的非对称性。     

雪热传导系数与穿过海冰的热通量研究

雪热传导系数是海冰质量平衡过程中的重要物理参数,决定了穿透海冰的热传导通量。北冰洋海冰质量平衡浮标观测获得多年冰上冬季温度链剖面可以明显地区分冰雪界面。本文考虑到冰雪界面处温度随时间变化,再根据冰雪界面热传导通量连续假定,提出了新的雪热传导系数计算方法。受不同环境因素影响,多年冰上各个浮标的雪热传导系数在0.23~0.41 W/（m·K）之间,均值为（0.32±0.08） W/（m·K）。北冰洋多年冰上冬季穿过海冰的热传导通量最大发生在11月至翌年3月,约14~16 W/m2。结冰季节,来自海冰自身降温的热量对穿过海冰向大气传输的热量贡献逐月减少,从9月100%减小到12月的35%,翌年的1月至3月稳定在10%左右。夏季,短波辐射通能量通过热传导自上而下加热海冰,海冰上层温度高于下层,热量传播方向与冬季反向,往海冰内部传递。直到9月短波辐射完全消失,气温下降,热量再次转变为自下往上传递。从冰底热传导来看,夏季出现海冰向冰水界面传递热量现象。由于雪较好的绝热性,冰上覆雪极大地削弱了海冰上层热传导通量,从而减缓了秋冬季节的结冰速度。尽管受雪厚影响,多年冰上层热传导通量与气温依旧具有很好的线性关系,气温每降低1℃,热传导通量增加约0.59 W/m2。     

The deep waters of the Eurasian Basin,Arctic Ocean: Geothermal heat flow,mixing and renewal

Hydrographic observations from four separate expeditions to the Eurasian Basin of the Arctic Ocean between 1991 and 2001 show a 300–700 m thick homogenous bottom layer. The layer is characterized by slightly warmer temperature compared to ambient, overlying water masses, with a mean layer thickness of 500±100 m and a temperature surplus of 7.0±2×10⁻³ °C. The layer is present in the deep central parts of the Nansen and Amundsen Basins away from continental slopes and ocean ridges and is spatially coherent across the interior parts of the deep basins. Here we show that the layer is most likely formed by convection induced by geothermal heat supplied from Earth's interior. Data from 1991 to 1996 indicate that the layer was in a quasi steady state where the geothermal heat supply was balanced by heat exchange with a colder boundary. After 1996 there is evidence of a reformation of the layer in the Amundsen Basin after a water exchange. Simple numerical calculations show that it is possible to generate a layer similar to the one observed in 2001 in 4–5 years, starting from initial profiles with no warm homogeneous bottom layer. Limited hydrographic observations from 2001 indicate that the entire deep-water column in the Amundsen Basin is warmer compared to earlier years. We argue that this is due to a major deep-water renewal that occurred between 1996 and 2001.     

Formation of Thermocline in the Equatorial Zone of the Oceans

We study the formation of the vertical distribution of temperature in the upper layer of the oceans (0– 300m) at low latitudes (10°N-10°S) by using the nonlinear dependence of the vertical heat flow on the vertical temperature gradient with regard for the influence of the bulk absorption of solar radiation and heat sink on the temperature of water. The thermocline is formed under the condition that the modulus of temperature gradient attains values for which their subsequent increase leads either to insignificant variations of the heat flow or even to its decrease. We consider the possibility of solution of inverse problems for the evaluation of the heat-exchange coefficient and the parameter of the heat sink. For the Equatorial Atlantic considered as an example, we compare the theoretical results with the data of instrumental measurements.__________Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 10–16, November–December, 2004.     

The Effect of Seasonal Variability of Atlantic Water on the Arctic Sea Ice Cover

Under the influence of global warming, the sea ice in the Arctic Ocean (AO) is expected to reduce with a transition toward a seasonal ice cover by the end of this century. A comparison of climate-model predictions with measurements shows that the actual rate of ice cover decay in the AO is higher than the predicted one. This paper argues that the rapid shrinking of the Arctic summer ice cover is due to its increased seasonality, while seasonal oscillations of the Atlantic origin water temperature create favorable conditions for the formation of negative anomalies in the ice-cover area in winter. The basis for this hypothesis is the fundamental possibility of the activation of positive feedback provided by a specific feature of the seasonal cycle of the inflowing Atlantic origin water and the peaking of temperature in the Nansen Basin in midwinter. The recently accelerated reduction in the summer ice cover in the AO leads to an increased accumulation of heat in the upper ocean layer during the summer season. The extra heat content of the upper ocean layer favors prerequisite conditions for winter thermohaline convection and the transfer of heat from the Atlantic water (AW) layer to the ice cover. This, in turn, contributes to further ice thinning and a decrease in ice concentration, accelerated melting in summer, and a greater accumulation of heat in the ocean by the end of the following summer. An important role is played by the seasonal variability of the temperature of AW, which forms on the border between the North European and Arctic basins. The phase of seasonal oscillation changes while the AW is moving through the Nansen Basin. As a result, the timing of temperature peak shifts from summer to winter, additionally contributing to enhanced ice melting in winter. The formulated theoretical concept is substantiated by a simplified mathematical model and comparison with observations.     

“暖池”表层对大气局地强迫的响应特征

利用湍流动能垂直混合模式和ＴＯＧＡ－ＣＯＡＲＥ加强观测期的观测资料,对“暖池”上混合层的垂直混合过程进行数值试验和数值模拟,分析表层温度、盐度的变化特征。结果表明：ＴＫＥ模式可以较好地模拟混层,尤其是表层温度、盐度对大气局地强迫的响应;太阳辐射是热源,感热、潜热通量等会造成“暖池”上混合层的温度降低,“暖池”对大气释放热量;降水有利于“淡水盖”形成和维持,从则使层结稳定,ＳＳＴ升高。但在气温低于海