A Long-Time-Step-Permitting Tracer Transport Model on the Regular Latitude–Longitude Grid

If an explicit time scheme is used in a numerical model, the size of the integration time step is typically limited by the spatial resolution. This study develops a regular latitude–longitude grid-based global three-dimensional tracer transport model that is computationally stable at large time-step sizes. The tracer model employs a finite-volume flux-form semiLagrangian transport scheme in the horizontal and an adaptively implicit algorithm in the vertical. The horizontal and vertical solvers are coupled via a straightforward operator-splitting technique. Both the finite-volume scheme's onedimensional slope-limiter and the adaptively implicit vertical solver's first-order upwind scheme enforce monotonicity. The tracer model permits a large time-step size and is inherently conservative and monotonic. Idealized advection test cases demonstrate that the three-dimensional transport model performs very well in terms of accuracy, stability, and efficiency. It is possible to use this robust transport model in a global atmospheric dynamical core.

Preface to the Special Issue on Changing Arctic Climate and Low/Mid-latitudes Connections

The Arctic climate system has changed rapidly during recent decades with a two-four times faster warming rate than the global average subject to the uncertainties of analysis datasets and approaches.These changes have apparently resulted in broader and sizeable impacts within the Arctic,in the low/mid-latitudes,and globally.The importance of these changes and impacts makes the Arctic stand out within the global climate systems,drawing great attention and interests from the climate research community,the general public,and the government sector.One of the persistent,leading-edge topics in climate stud-ies during recent decades has therefore been to improve understanding of the underlying driving mechanisms,evaluate socioe-conomic and ecological impacts,and enhance the ability of the prediction and projections of Arctic climate changes.

Association between Temperature Changes and Cardiovascular Mortality Risk in A High-latitude City in Northeast China

In recent decades,regional and global climate change has increased the frequency of extreme weather events(e.g.,hurricanes,cold spells,and heat waves).The diurnal temperature range(DTR)and temperature change between neighboring days(TCN),which are indicators of short-term temperature shifts.

轻量设计为商业用户减负戴尔Latitude 7440超轻版

如今,移动办公、混合办公已经成为很多企业以及商务人士所推崇的办公模式,在这种更加自由灵活的办公模式下,商业用户对笔记本电脑也提出了新的要求—既要轻薄便携、长续航,又要坚固耐用,还要安全可靠。能够同时满足这些要求的只有专业的商务本产品,而在商务本领域。

Ionospheric Currents in the Equatorial and Low Latitudes of Africa

The magnetometer data obtained for 2008 from geomagnetic stations installed across Africa by magnetic data acquisition set (MAGDAS) have been used to study the ionospheric Sq current system in the equatorial and low-latitudes of Africa. The aim of this work is to separate the quiet-day field variations obtained in the equatorial and low latitude regions of Africa into their external and internal field contributions and then to use the paired external and internal coefficients of the SHA to determine the source current and induced currents. The method used involved a spherical harmonic analysis (SHA). This was applied in the separation of the internal and external field/current contribution to the Sq variations. The result shows that the variation in the currents is seen to be a dawn-to-dusk phenomenon with the variation in the external currents different from that of the internal currents both in amplitude and in phase. Furthermore, the seasonal variation in the external current maximizes during the March equinox and minimizes during the December solstice. The maximum current observed in AAB and ILR is due to the Equatorial Electrojet Current present in the AAB and ILR stations. Seasonal variation was observed in the geomagnetic component variations as well as in the currents. This is attributed to the position of the sun with respect to the earth at different months of the year. The equinoctial maximum is observed in external current intensity which occurred mostly during the March Equinox.

戴尔推出新一代Latitude笔记本

电池续航时间长达9．4个小时的笔记本电脑，对那些经常出差在外地的商务人士无疑具有极大的诱惑力。这在以前不敢想象的事情如今已经发生在眼前。5月17日，在英特尔发布新款酷睿2代双核处理器一周之后，戴尔推出的两款新型商用笔记本电脑Latitude D630和D830就是为这些商务人士精心打造的一款产品。

Pathways of Influence of the Northern Hemisphere Mid–high Latitudes on East Asian Climate: A Review

This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid-high latitudes on East Asian climate within the framework of a“coupled oceanic-atmospheric(land-atmospheric or seaice-atmospheric)bridge”and“chain coupled bridge”.Four major categories of pathways are concentrated upon,as follows:Pathway A—from North Atlantic to East Asia;Pathway B—from the North Pacific to East Asia;Pathway C—from the Arctic to East Asia;and Pathway D—the synergistic effects of the mid-high latitudes and tropics.In addition,definitions of the terms“combined effect”,“synergistic effect”and“antagonistic effect”of two or more factors of influence or processes and their criteria are introduced,so as to objectively investigate those effects in future research.

谷歌的Latitude与威客地图

如果说Google是基于电脑的搜索引擎,那么威客地图则是基于人脑的搜索引擎。随着全球网络向智能化迈进,人脑取代电脑将是必然。看来,Google要当心了。

Chinese Antarctic Magnetometer Chain at the Cusp Latitude

A Chinese Antarctic Magnetometer （CAM） chain from Zhongshan Station （ZHS） to Dome-A （DMA） has been established since February 2009. A regular magnetometer is operated at ZHS, and four low power magnetometers are operated along the interior route from ZHS to DMA in the cusp latitude, extending over a distance of 1260 km. These stations fill an important void in the Antarctic magnetometer network. Furthermore, the CAM chain is magnetically conjugated with the Arctic region reaching from the Svalbard archipelago to Daneborg, on the east coast of Greenland. Conjugate measurements using the Arctic and Antarctic magnetometers provide excellent opportunities to investigate phenomena related to the coupling of the solar wind to the magnetosphere and ionosphere, such as magnetic impulse events, flux transfer events, traveling convection vortices and ultra-low frequency waves.

EISCAT Observations of Main Ionization Troughs in the High-Latitude Ionosphere

F-region electron density depletions associated with main ionization troughs in the high-latitude ionosphere are studied using EISCAT CP3 data of meridian scanning experiments. The troughs in our observations are found to appear mainly in dusk sector, extending from late afternoon to pre-midnight, with higher occurrence rate during equinox and winter. Simultaneous ion drift velocity inF-region shows that the main trough minimum is mostly located at the equator ward edge of the plasma convection flow, rather than in the region where the largest ion flow are observed.

Sea surface temperature evolution in the Yellow Sea Warm Current pathway and its teleconnection with high and low latitude forcing during the mid-late Holocene

Sea surface temperature(SST)in the Yellow Sea Warm Current(YSWC)pathway is sensitive to the East Asian Winter Monsoon(EAWM)and YSWC.However,the role of the YSWC in the evolution of regional SST remains unclear.Here,we present new U 37 k′based SST and grain size sequences spanning the last 6092 years in the sediment core Z1,which was retrieved from the central Yellow Sea muddy area.Overall,U 37 k′-SST gradually increased since 6.1 ka BP,with a series of centennial-scale fl uctuations.Its variation was mainly caused by EAWM when YSWC was weak between 6.1 and~3.9 ka BP,as shown by the end-member content of grain size.However,after YSWC was fully developed,i.e.,since~3.9 ka BP,it exerted critical eff ects on SST evolution in its pathway.The 1010-and 538-year cycles of the SST sequence indicated a basic control of solar activity on the oceanic conditions in the Yellow Sea.It is suggested that the variation of total solar irradiance was amplifi ed by thermohaline circulation and then transmitted to the Yellow Sea through the EAWM.Meanwhile,the tropical Pacifi c signal of El Niño was transmitted to the YSWC through the Kuroshio Current.The dual properties of warm water transported by YSWC to compensate the EAWM and driving by Kuroshio Current closely linked the variation of SST in the YSWC pathway to the Northern Hemisphere high latitude climate and the tropical Pacifi c.These fi ndings highlight the signifi cance of YSWC on regional SST evolution and its teleconnection to high and low latitude forcing,which grains a better understanding of the long-term evolution of SST in the middle latitude Yellow Sea.

Unmanned Aerial Vehicle Control of Major Sugarcane Diseases and Pests in Low Latitude Plateau

This research was aimed at the defects in traditional artificial spraying control method and the problems such as the difficulty in pesticides applying,labor shortage and low operating efficiency in the middle and late stage of sugarcane high stalk crops.The aerial pesticide application technology for sugarcane main diseases and pests was systematically developed and demonstrated from the aspects of aircraft type choice,selection of special pesticides and auxiliaries,integration of pesticides and equipment,field operation,technical specifications,and large-scale application organization mode.The UAV model and flight technical parameters suitable for the sugarcane planting area in low-latitude plateau were analyzed,and the optimal agent formulation combination and application technology of the UAV flight control were screened out,and the UAV flight control was applied to the major sugarcane pests and diseases control in the low-latitude plateau in large scale(UAV flight control was popularized and applied to 15 527 hm 2 in 2018).The research results provided mature whole-process technical support for the normalization of the application of the UVA flight control of major sugarcane pests and diseases.The UAV control technology for major sugarcane pests and diseases had the advantages of ultra-low pesticides applying dosage and high operating efficiency,and could effectively solve the problems such as the difficulty in pesticides applying,labor shortage and low operating efficiency in the middle late growth stage of high stalk crops.This technology successfully opened up a simple,efficient and new way for the effective control of major sugarcane pests and diseases,and practically accelerated the process of integrated control and prevention of sugarcane pests and diseases.In addition,this technology had an extremely significant effect on reducing the loss of sugarcane farmers and enterprises caused by the epidemic and outbreak of sugarcane pests and diseases,increasing sugarcane yield and sugar content.At the same time,this technology played an important role in realizing the whole-process precise control of sugarcane pests and diseases,improving the quality and increasing the efficiency of sugarcane,and guaranteeing the national sugar safety.

International Comparison and Implications of Agricultural Development in Foreign Low Latitude Plateau Regions for Yunnan Province

Climatic characteristics of foreign low latitude plateau regions are firstly introduced.Then,experience and lessons of major foreign low latitude plateau countries in developing modern agriculture are analyzed,including Indian three agricultural revolutions and agricultural informationization development,application of agricultural biotechnology in Brazil,trade liberalization and economic de-agriculture of Mexico,and Argentina,Saudi Arabia and South Africa attaching great importance to developing modern agriculture relying on science and technology and paying close attention to resource conservation and environmental protection.Combining natural and social resource characteristics of Yunnan plateau agriculture,pertinent implications and recommendations for modern agricultural development in Yunnan are put forward.Specifically,these include strengthening agricultural sci-tech research and development,and extension and application;transforming agricultural development model;enhancing agricultural resource conservation and environmental protection;accelerating developing mountain organic ecological agriculture and autumn agriculture;reinforcing urban and rural integration to develop plateau characteristic agriculture on the basis of local actual conditions.

Propagation characteristics of the Pc3 frequency range pulsations in the cusp latitudes

Two induction magnetometers have been installed at Zhongshan Station and Davis Station, Antarctica respectively. We adopt with cross-spectral analysis technique to analyze the data of the two induction magnetometers, in June, September,December 1996 and March 1997. to investigate the Pc3 frequency range pulsation occurrence and propagation characteristics in the cusp latitudes. The results are summarized as following:At Zhongshan-Davis Stations, the Pc3 frequency range pulsations occur mainly around the local noon/ local magnetic noon and local magnetic midnight respectively. In daytime, the pulsations have a seasonal variation in amplitude, occurrence and temporal range, all of them are sma1lest in winter. But in nighttime, the pulsations have no such a variation. The pu1sation amplitude in nighttime is much larger than the one in daytime all oveI the year. The pulsation propagating direction is mainly western in daytime and irregularly in nighttime. It can be thought that the different sources of the pulsation and the ionospheric electric conductivity are mainly responsible for these characteristics.

Preliminary research on dissolved oxygen maximum of seawater in low latitude of China

-During the multi-disciplinary investigations on the waters of Nansa Islands for three cruises respectively in 1985. 1986. 1987. it is found that the dissolved oxygen maximum (DOmax) in its vertical distribution usually exists between 20m and 75m deep. The deep position of O2 maximum is near the thermocline below and above the deep chlorophyll maximum, as well as above the light-beam attenuation coefficient maximum. In the parts of O2 maximum occurring, the minimum of CO2 partial pressure and the maximum of pH value are also found at the same depth. It is still difficult to explain the features exactly by using the published research results about the oxygen maximum in its vertical distribution on the waters of middle and high latitude.In the present paper, the dissolved oxygen maximum in its vertical distribution on the waters of low latitude is described. It is made by an internal wave which holds eddy mixture. The feature appears to arise from the biological photosynthesis with stratification, from the action of the thermocline preventing oxygen from escaping to the atmosphere, when the environment is suitable for organisms to grow.

ON THE COMPUTATION OF THE VERTICAL VELOCITY AT THE TOP OF PBL IN LOW LATITUDE AREAS

This paper suggests a mcthod to eompute the verticaI velocity at the top of PBL Jn low latitude areas by use of the wind data on (sea) surfaca and some characteristics of the vcrtical velocity are shownThe results show the important rolcs played by the incrtial forces and β

A New Perspective of the Physical Processes Associated with the Clear-Sky Greenhouse Effect over High Latitudes

The physical processes associated with the clear-sky greenhouse effect in the presence of water vapor are examined by including surface emissivity in the greenhouse effect formulation, and by introducing a new way to partition physical processes of the greenhouse effect. In this new framework, it is found that the clear-sky greenhouse effect is governed by three physical processes associated with (1) the temperature contrast between the surface and the atmosphere, (2) the interaction between the surface emissivity and the temperature contrast, and (3) the surface emissivity. The importance of the three physical processes is assessed by computing their vertical and spectral variations far the subarctic winter and summer standard atmosphere using the radiation model MODTRAN3 (Moderate Resolution Transmittance code Version 3). The results show that the process associated with the temperature contrast between the surface and the atmosphere dominates over the other two processes in magnitude. The magnitude of this process has substantial variations in the spectral region of 1250 to 1880 cm-1 and in the far infrared region. Due to the low-level temperature inversion over the subarctic winter, there exists a negative contribution to the greenhouse trapping. The seasonal variations are, however, dominated by the processes associated with the interaction between the surface emissivity and the temperature contrast as well as the surface emissivity itself. The magnitudes of these two physical processes contributing to the greenhouse trapping over the subarctic winter are about 7 to 10 times of those over the subarctic summer, whereas the magnitude of the processes associated with the temperature contrast in the subarctic summer is only about 2 times of that in the subarctic winter.

Comparison of methods to transition geodetic latitude

With the wide application of GPS technology, the application of the system of space rectangular coordinates is more and more extensive. Transformation of space rectangular coordinates into geodetic coordinates becomes a very popular problem. In order to evaluate various kinds of algorithms existing for solving the problem, three evaluation criteria of the algorithm were put forward at first, that is, precision, calculation speed and algorithm regional suitability. After given some basic formula, three kinds of representative algorithms, classics iteration algorithm, ellipsoidal parameter transformation algorithm and rational polynomials approximation algorithm were introduced. Through a test program made by MATLAB, these three kinds of algorithms were compared. Some helpful conclusions were drawn.

Integration and Application of Comprehensive Prevention and Control Technology for Sugarcane Borers in Low Latitude Plateau of China

Aimed at the difficult problem of prevention and control of disastrous sugarcane borers in low latitude plateau of China,this research systematically overcame the bottleneck of comprehensive prevention and control of sugarcane bores after 10 years of collaborative research,and formed a number of core product technologies,which promoted the green and high-quality development of the sugarcane industry and achieved the following innovative results.In this study,the species,population structure and damage characteristics of disastrous sugarcane borers in low latitude plateau were clarified for the first time,which provided a scientific basis for the formulation of technology and application of comprehensive prevention and control.The monitoring technology system and early warning monitoring network were constructed for the monitoring of borer population in low latitude plateau sugarcane area,which realized the accurate monitoring of the population dynamics of sugarcane bores and provided technical support for comprehensive prevention and control.The flight spraying technology by unmanned aerial vehicle(UAV)was developed for bores in the low latitude plateau cane area,and it has been successfully applied in a large area,thereby opening up a new way of light,simple and efficient for effective control of borers.The scale application of lamp trapping and sexual attracting to kill adult insects technology promoted the advancement of green control technology of bores.Integration was made to the comprehensive control techniques like UAV flight control,biological agents,physical and chemical inducement and control,and sexual attractant trapping in the low latitude plateau sugarcane area,and standardized technical regulations have been formulated,which significantly improved the overall prevention and control effect of large areas.The technologies for the comprehensive prevention and control of sugarcane borers have been popularized and applied in 8 major sugarcane producing states(cities)in low altitude plateau of Yunnan over the years,which has controlled the damage and showed remarkable control effect.In 2017-2018,the integrated control technology was popularized and applied to a total of 2.78×10^5 hm^2(1.33×10^4 hm^2 of UAV flight control)of area,which recovered a total of 3.666×10^6 t of sugarcane losses,increasing 4.69×10^5 t of sugar with the sales increase of 3.979 billion yuan,added profits of 1.251 billion yuan and the taxes increase of 188 million yuan.The research results show that the technology has high technical integration,strong practicability,high degree of transformation,significant economic,social and ecological benefits,which provide technical supports for the sustainable development,loss reduction and efficiency increase of the sugarcane industry in the low-latitude plateau sugarcane region,and make significant contributions to the economic development of ethnic minorities in the border-stricken areas and the increase of farmers income and poverty alleviation.