Interannual variability of latent and sensible heat fluxes in the South China Sea

The South China Sea (SCS) is significantly influenced by El Nio and the Southern Oscillation (ENSO) through ENSO-driven atmospheric and oceanic changes.We analyzed measurements made from 1960 to 2004 to investigate the interannual variability of the latent and sensible heat fluxes over the SCS.Both the interannual variations of latent and sensible heat fluxes are closely related to ENSO events.The low-pass mean heat flux anomalies vary in a coherent manner with the low-pass mean Southern Oscillation Index ...     

An improved algorithm of simulation on air-sea turbulent heat fluxes in China seas

With a global GSSTF2 and NCEP/NCAR reanalysis database and observation data at the Yong Xing station of Xisha Island in the South China Sea, we simulated the turbulent sensible and latent heat flux at sea surface in Chinese and neighboring seas (hereafter termed as China seas) using a common bulk method with some improved parameters. Comparing the simulated results with the observed and reanalyzed data, the improvement yielded higher accuracy, a smaller mean square deviation within 10 W/m2, and a smaller average relative error at about 25%. In addition, spatial resolution was improved to 0.1°×0.1°. The simulation is able to replay the main features of regional and seasonal variation in turbulent heat fluxes, and also the general pattern of heat flux changes during the summer monsoon outbreak in the South China Sea.     

Interdecadal variability of the South China Sea monsoon and its relationship with latent heat flux in the Pacific Ocean

We analyzed interdecadal variability of the South China Sea monsoon and its relationship with latent heat flux in the Pacific Ocean, using NCEP wind field and OAFlux heat flux datasets. Results indicate that South China Sea monsoon intensity had an obvious interdecadal variation with a decreasing trend. Variability of the monsoon was significantly correlated with latent heat flux in the Kuroshio area and tropical Pacific Ocean. Variability of latent heat flux in the Kuroshio area had an interdecadal increasing trend, while that in the tropical Pacific Ocean had an interdecadal decreasing trend. Latent heat flux variability in these two sea areas was used to establish a latent heat flux index, which had positive correlation with variability of the South China Sea monsoon. When the latent heat flux was 18 months ahead of the South China Sea monsoon, the correlation coefficient maximized at 0.58 (N=612), with a 99.9% significance level of 0.15. Thus, it is suggested that latent heat flux variability in the two areas contributes greatly to interdecadal variability of the South China Sea monsoon.     

STUDY ON FLUXES OF MOMENTUM AND SENSIBLE HEAT,THE DRAG COEFFICIENT C_D AND ROUGHNESS Z_O

In this paper,fluxes of momentum and sensible heat are discussed with the data callected by tetheredballoon sounding system over the Philippine Sea during the cruise of the R/V SCIENCE 1 from Septem-ber through October in 1987.These fluxes were calculated using the semiempirical flux-profile relationshipsof Monin-Obkhov similarity theory with observed data.The friction velocity U.was determined by theobserved data's least-square fit with the similarity formulae under stable,neutral and unstable conditions.The roughness Z_0 was determined by Z_0=a_1(U./g),then substituted into the similarity formulae to com-pute U.again.The final values of U.and Z_0 could be determined through this iteration.The fluxtemperature θ.was calculated from the temperature profile with Z_0 determined above.Finally the fluxes'of momentum and sensible heat,and the drag coefficient C_D were obtained by computation with U.,θ.and the wind speed(U_(10))at 10 meters above the sea surface.     

Analysis of atmospheric turbulence in the upper layers of sea fog

Atmospheric turbulence plays a vital role in the formation and dissipation of fog. However,studies of such turbulence are typically limited to observations with ultrasonic anemometers less than 100 m above ground. Thus,the turbulence characteristics of upper fog layers are poorly known. In this paper,we present 4-layers of data,measured by ultrasonic anemometers on a wind tower about 400 m above the sea surface; we use these data to characterize atmospheric turbulence atop a heavy sea fog. Large differences in turbulence during the sea fog episode were recorded. Results showed that the kinetic energy,momentum flux,and sensible heat flux of turbulence increased rapidly during the onset of fog. After onset,high turbulence was observed within the uppermost fog layer. As long as this turbulence did not exceed a critical threshold,it was crucial to enhancing the cooling rate,and maintaining the fog. Vertical momentum flux and sensible heat flux generated by this turbulence weakened wind speed and decreased air temperature during the fog. Towards the end of the fog episode,the vertical distribution of sensible heat flux reversed,contributing to a downward momentum flux in all upper layers. Spatial and temporal scales of the turbulence eddy were greater before and after the fog,than during the fog episode. Turbulence energy was greatest in upper levels,around 430 m and 450 m above mean sea level(AMSL),than in lower levels of the fog(390 m and 410 m AMSL); turbulence energy peaked along the mean wind direction. Our results show that the status of turbulence was complicated within the fog; turbulence caused fluxes of momentum and sensible heat atop the fog layer,affecting the underlying fog by decreasing or increasing average wind speed,as well as promoting or demoting air temperature stratification.     

青藏高原土壤热交换的计算方案及初步分析

从地温满足的热传导方程出发，导出了计算土壤平均和瞬时热通量的计算方案。该计算方案可同时计算出土壤热通量随时间和随深度的变化。它利用整层的地温信息来计算任一层的热通量，这种方案克服了用差分方案进行直接计算的局限性。然后使用中日亚洲季风观测实验期间的地温自动观测站资料和相应的常规观测资料，计算了青藏高原上土壤热通量及其变化，结果表明，不论是常规观测站还是自动观测站，其结果与青藏高原第一次观测实验所用热流板的直接观测结果是相近的，因而这种计算方案是实用而有效的。     

Contribution of oceanic circulation to the polewar heat flux

Oceanic contribution to the poleward heat flux in the climate system includes two components: the sensible heat flux and the latent heat flux. Although the latent heat flux has been classified as atmospheric heat flux exclusively, it is argued that oceanic control over this component of poleward heat flux should play a critically important role. The so-called swamp ocean model practice is analyzed in detail, and the critical role of oceanic circulation in the establishment of the meridional moisture transport is emphasized.     

Contribution of Oceanic Circulation to the Poleward Heat Flux

Oceanic contribution to the poleward heat flux in the climate system includes two components： the sensible heat flux and the latent heat flux. Although the latent heat flux has been classified as atmospheric heat flux exclusively, it is argued that oceanic control over this component of poleward heat flux should play a critically important role. The so-called swamp ocean model practice is analyzed in detail, and the critical role of oceanic circulation in the establishment of the meridional moisture transport is emphasized.     

SEASONAL HEAT BUDGET IN THE TROPICAL WESTERN PACIFIC OCEAN IN A GLOBAL GCM Ⅱ. IN FIVE SUBREGIONS

The general features of the seasonal suuface heat budget in the tropical western Pacific Ocean,20°S-20°N, western boundary-160°E, were documented by Qu (1995) using a high-resolution generalcirculation model (GCM, Semtner & Chervin,1992) ard existing observations.Close inspection of thesmaller areas, with the whole region further partitioned into six parts, showed different mechanisms balancethe seasonal surface heat budget in different parts of the region The results of study on five subregionsare detailed in this article. In the equatorial (3°S - 3°N) aed North Equatorial Countercurrent(3°N-9°N) region, the surface the flux the does not change significantly throughout the year, so the surface heat content is determined largely by vertical motion near the equator and roughly helf due to horizontal and halfdue to vertical circulation in the region of the North Equatorial Countercurrent(NECC). In the othersubregions (9°N-20°N, 20°S -11°S aed 11°S -3°S ), however, in addition to ocean dynamics     

Seasonal heat budget in the tropical Western Pacific Ocean in a global GCM II. In five subregions

The general features of the seasonal surface heat budget in the tropical western Pacific Ocean, 20° S–20°N, western boundary −160°E, were documented by Qu (1995) using a high-resolution general circulation model (GCM, Semtner & Chervin, 1992) and existing observations. Close inspection of the smaller areas, with the whole region further partitioned into six parts, showed different mechanisms balance the seasonal surface heat budget in different parts of the region. The results of study on five subregions are detailed in this article. In the equatorial (3°S–3°N) and North Equatorial Countercurrent (3°N–9°N) region, the surface heat flux does not change significantly throughout the year, so the surface heat content is determined largely by vertical motion near the equator and roughly half due to horizontal and half due to vertical circulation in the region of the North Equatorial Countercurrent (NECC). In the other subrigions (9°N–20°N, 20°S–11°S and 11°S–3°S), however, in addition to ocean dynamics, surface heat flux can also play a major role in the seasonal variation of sea surface temperature (SST). The remotely forced baroclinic waves and their effect on the surface heat storage in the model are also investigated. Comparison with observations indicates that the model wave activities are reasonably realistic. Contribution No. 2396 from the Institute of Oceanology, Chinese Academy of Sciences. This study was supported by the Australian CSIRO Division of Oceanography and the National Natural Science Foundation of China (No. 49176255)     

Spatiotemporal features and possible mechanisms of seasonal changes in sea surface height south of Japan

Variations of sea surface height(SSH) in the Kuroshio south of Japan are addressed by analyzing 19-year(1993–2011) altimetry data from AVISO. Regionally averaged time series of observed SSH had a rising linear trend at 2.64±0.72 mm/a in this period. By analyzing the power spectra, several periods were recognized in temporal SSH variations, including those around 90 and 360 days. The seasonal cycle of SSH was minimum in winter(February) and maximum in summer(August), with peak-to-peak amplitude about 20.0 cm. The spatial distribution of linear trends was inhomogeneous, with a rising linear trend along the coastline and a tripole structure offshore. Spatial distributions of standard deviation of seasonal SSH show very dynamic activities in the southeast of Kyushu and south of Honshu. Seasonal variations of observed SSH are partially explained by surface buoyancy forcing, local wind forcing and the steric component related to subsurface water beneath the mixed layer. Results show different spatial distributions of correlation coefficient and estimation skill between seasonally observed and modeled SSH, which are calculated from surface buoyancy fl ux, local wind forcing and the steric component related to subsurface water. Of those three, the surface buoyancy fl ux has a greater contribution to variations of observed SSH on the seasonal time scale south of Japan.     

THERMAL EFFECTS OF BUILDING′S EXTERNAL SURFACES IN CITY——Characteristics of Heat Flux into and out of External Wall Surfaces

1INTRODUCTIONWiththerecentmodernizationandurbanizationofChi-na,urbanareashavegreatlyincreased, andgiantbuild-ings,especiallythosetallerthan100m,havebeendomi-nantincities,whichhave resultedinthegreatincreaseintheproportionofbuilding'sexternalsurfacetototalurbanarea.Thedifferencesofthermalpropertiesmain-lyinducedbysolarradiationbetweenbuilding'sexter-nalsurfacesareobviousfordifferentexposures,whichcaninevitablyinfluencethedistributionsofairtempera-turenearby,eventheverticaldistributionsofurb…     

Circulation and Heat Flux along the Western Boundary of the North Pacific

On the basis of the conductivity temperature depth(CTD)observation data off the coast of the Philippines(7.5°–18°N,130°E–the east coast of the Philippines)in the fall of 2005,the water mass distribution,geostrophic flow field,and heat budget are examined.Four water masses are present:the North Pacific Tropical Surface Water,the North Pacific Sub-surface Water,the North Pacific Intermediate Water,and the Antarctic Intermediate Water(AAIW).The previous three corresponded with the North Equatorial Current(NEC),the Kuroshio Current(KC),and the Mindanao Current(MC),respectively.AAIW is the source of the Mindanao Undercurrent.The mass transport of NEC,KC,and MC is 58.7,15,and 27.95Sv,respectively(relative to 1500db).NEC can be balanced by the transport across the whole transect 18°N(31.81 Sv)and 7.5°N(26.11 Sv)but not simply by KC and MC.Direct calculation is used to study the heat flux.In sum,1.45PW heat is transported outwards the observed region,which is much more than that released from the ocean to the air at the surface(0.05PW).The net heat lost decreased the water temperature by 0.75℃each month on average,and the trend agreed well with the SST change.Vertically,the heat transported by the currents is mainly completed in the upper 500 m.     

SEASONAL HEAT BUDGET IN THE TROPICAL WESTERN PACIFIC OCEAN IN A GLOBAL GCMⅠ.GENERAL DESCRIPTION

This paper describes the large scale aspects of the seasonal surface heat budget and discusses itsmain forcing mechanisms in the tropical Western Pacific Ocean.The high-resolution generalcirculation model (Semtner & Chervin,1992)used in this study reproduced well the observed upper-layer thermal structure and circulation.It is shown that at least on the average of the study region(20°S-20°N,west boundary-160°E)the semiannual variation is a dominant signal for all heat budgetcomponents and is presumably due to the sun’s passing across the equator twice a year,but that thecomponents have substantial differences in amplitude.The local Ekman divergence in the region doesnot change significantly through the year.As a result,the change in surface heat content is roughlyhalf due to ocean-atmosphere heat exchange and half due to heat advection by remotely forced verti-cal motion.Horizontal currents do not play a significant role directly by advection,because the wat-er which enters the region is not very muc     

卫星热遥感技术在地震预测中应用研究进展

已有的研究结果表明。许多强地震前存在热异常。异常的表现形式是多种多样的，异常的时空分布与异常区的地质构造、地理环境、季节、天气等因素有关。内陆地区的地震前常产生热红外异常，而沿海地区的地震前则更容易出现潜热通量异常。红外辐射可以通过卫星红外通道的传感器观测到。而潜热通量可以使用微波遥感观测资料计算或红外遥感与地面观测资料联合反演。应用卫星遥感技术研究地震前的热异常虽然目前仍然存在许多问题，但随着技术的进步和研究工作的深入，应该能在地震预测中发挥重要作用。     

三峡库区典型样带潜热通量遥感反演与验证

本文以三峡库区腹地的部分地区为典型样带,利用遥感数据的时效性和区域性优势,结合常规气象数据,定量反演样带地表潜热通量,并对比验证遥感反演方法的可行性和可靠性。结果表明：潜热通量在不同地表覆被状况下呈现较大差异,城镇居民区和无植被覆盖区一般在20~80W·m^-2;人工林场、山区森林及草灌和山前农作区在180~280W·m^-2;水体则分布在420~470W·m^-2,潜热通量整体呈现出随地表覆被变化而变化的空间异质性。此外,由于库区地表覆被类型多样,并受到山区起伏地形地貌的影响,潜热通量在空间分布上的地形分异特征也较显著。     

中国地级市人为热总量的估算及驱动因素分析

人为热一定程度上影响着城市的局地环境和微气候。以2016年中国地级市为研究对象,首先采用了能源消耗清单法结合Suomi-NPP（National Polar-orbiting Partnership）VIIRS（Visible Infrared Imaging Radiometer Suite）夜间灯光数据的方法估算了格网尺度的人为热通量;其次,分别使用最小二乘法和地理加权回归法模型在全局和局部尺度上研究不同因素对人为热总量的影响;进一步使用自然断点法划分出其中的主导因素。得出以下结论：① 各地级市的人为热总量具有显著的空间差异,京津冀、长江三角洲、珠江三角洲城市群所在的中国东南地区,人为热总量相对较高;② 能源消耗、民用汽车数量、人均生产总值是全局尺度上人为热总量的主要驱动因素;人口密度、第二产业占比、道路密度和建成区面积对人为热总量的影响呈现出较强的空间异质性;外商直接投资额则在全局尺度对人为热总量的影响较低。③ 主导因素分析表明无主导因素的地级市主要位于中国的西南部,以能源消耗、民用汽车数量、人均生产总值为单一主导因素的地级市主要聚集于中国的东南部、中部及东北部、西北部,并在其周边交叉地区形成了一些数量较少的双重主导因素地级市。本文的研究为政府相关部门对于人为热调控政策的制定提供了依据。     

Estimates of global M_2 internal tide energy fluxes using TOPEX/POSEIDON altimeter data

TOPEX/POSEIDON altimeter data from October 1992 to June 2002 are used to calculate the global barotropic M2 tidal currents using long-term tidal harmonic analysis. The tides calculated agree well with ADCP data obtained from the South China Sea (SCS). The maximum tide velocities along the semi-major axis and semi-minor axis can be computed from the tidal ellipse. The global distribution of M2 internal tide vertical energy flux from the sea bottom is calculated based on a linear internal wave generation model. The global vertical energy flux of M2 internal tide is 0.96 TW, with 0.36 TW in the Pacific, 0.31 TW in the Atlantic and 0.29 TW in the Indian Ocean, obtained in this study. The total horizontal energy flux of M2 internal tide radiating into the open ocean from the lateral boundaries is 0.13 TW, with 0.06 TW in the Pacific, 0.04TW in the Atlantic, and 0.03 TW in the Indian Ocean. The result shows that the principal lunar semi-diurnal tide M2 provides enough energy to maintain the large-scale thermohaline circulation of the ocean.     

SEAWATER FLUX OF THE SOUTH CHINA SEA

The South China Sea water can be divided according to depth into three boxes by the pycnoclineand a sill.Using a box model with matter balance,the net seawater fluxes were calculated to be317.9×10~4 m~3/s in box Ⅰ for the upper homogeneous layer outflowing to the adjoining oceans;67×10~4 m~3/s in box Ⅲ for the water entering the basin;240×10~4 m~3/s in box Ⅱ for water entering theSouth China Sea.The upward speed of basin water was calculated to be 8.4×10~(-5) cm/s and that ofseawater flowing up along the pycnocline was calculated to be 8.9×10~(-5) cm/s.     

Modeling vertical heat transport in the wave affected surface layer of the ocean

In considering the vertical heat transport problems in the upper ocean, the flat upper boundary approximation for the free surface and the horizontal homogenous hypothesis are usually applied. However, due to the existence of the wave motion, the application of this approximation may result in some errors to the solar irradiation since it decays quickly in respect to the actual thickness of the water layer below the surface; on the other hand, due to the fluctuation of the water layer depth, it is improper to neglect the effects of the horizontal advection and turbulent diffusion since they also contribute to the vertical heat transport. A new model is constructed in this study to reflect these effects. The corresponding numerical simulations show that the wave motion may remarkably accelerate the vertical heat transferring process and the variation of the temperature in the wave affected layer appears in an oscillating manner. Supported by the National High Technology Research and Development Program of China (863 Program, No. 2006AA09A309); China Postdoctoral Science Foundation (No. 20070411111) and the Fund of Shandong Province for the Excellent Post-Doctors (No. 200603056)