Florida current: seasonal and interannual variability

Annual and interannual variations in the Florida Current, Caribbean, and subtropical Atlantic are investigated with the use of historical sea level differences and wind field data. Observational and model evidence suggests that the seasonal transport cycle of the Florida Current is locally forced, either upstream in the Caribbean or downstream over topography. Although at seasonal and shorter periods sea level or bottom pressure fluctuations on the left side of the Florida Current contribute almost all of the variance of sea level difference across the Florida Straits and hence transport, this relation does not seem to apply at interannual time scales. Using results from the Subtropical Atlantic Climate Studies, it is estimated from historical sea level data that interannual transport fluctuations of the Florida Current are only of order 1 x 10(6) cubic meters per second. Interannual fluctuations in the 2- to 3-year period range in the Florida Straits seem to be correlated with sea level differences across the Caribbean and the subtropical Atlantic but not with Sverdrup transport fluctuations in the subtropical Atlantic.     

Sea level variation as an indicator of Florida current volume transport: comparisons with direct measurements

Sea level measurements from tide gauges at Miami, Florida, and Cat Cay, Bahamas, and bottom pressure measurements from a water depth of 50 meters off Jupiter, Florida, and a water depth of 10 meters off Memory Rock, Bahamas, were correlated with 81 concurrent direct volume transport observations in the Straits of Florida. Daily-averaged sea level from either gauge on the Bahamian side of the Straits was poorly correlated with transport. Bottom pressure off Jupiter had a linear coefficient of determination ofr(2) = 0.93, and Miami sea level, when adjusted for weather effects, had r(2) = 0.74; the standard errors of estimating transports were +/- 1.2 x 10(6) and +/- 1.9 x 10(6) cubic meters per second, respectively. A linear multivariate regression, which combined bottom pressure, weather, and the submarine cable observations between Jupiter and the Bahamas, had r(2) = 0.94 with a standard error of estimating transport of +/- 1.1 x 10(6) cubic meters per second. These results suggest that a combination of easily obtained observations is sufficient to adequatelv monitor the daily volume transport fluctuations of the Florida Current.     

Sceloporus occidentalis: Preferred Body Temperature of the Western Fence Lizard

Given equal thermal opportunities during four seasonal test periods, western fence lizards active above ground preferred constant body temperature throughout the year. Lizards recovered from subsurface retreats in the fall exhibited a mean body temperature significantly lower than that for sequestered lizards recorded during winter, spring, and summer.     

The Earth's Angular Momentum Budget on Subseasonal Time Scales

Irregular length of day (LOD) fluctuations on time scales of less than a few years are largely produced by atmospheric torques on the underlying planet. Significant coherence is found between the respective time series of LOD and atmospheric angular momentum (AAM) determinations at periods down to 8 days, with lack of coherence at shorter periods caused by the declining signal-to-measurement noise ratios of both data types. Refinements to the currently accepted model of tidal Earth rotation variations are required, incorporating in particular the nonequilibrium effect of the oceans. The remaining discrepancies between LOD and AAM in the 100- to 10-day period range may be due to either a common error in the AAM data sets from different meteorological centers, or another component of the angular momentum budget.     

Volume and heat transports of the Florida current: april 1982 through august 1983

Absolute velocity and temperature profiles are used to estimate the volume transport through the Straits of Florida and, in combination with historical midbasin data, to estimate the total meridional heat flux through a section at 27 degrees N. The mean annual volume transport of the Florida Current from April 1982 through August 1983 is 30.5 (+/- 1)x 10(6) cubic meters per second. The net northward heat flux through the 27 degrees N section is 1.2 (+/- 0.1)x 10(15) watts. The volume transport is characterized by high values in the late spring and early summer and low values in the late fall and early winter. There is a similar cycle in total heat flux.     

The Ogallala Agro-Climate Tool

A Visual Basic™ agro-climate application capable of estimating crop evapotranspiration and irrigation demand over the Ogallala aquifer region is described here. The application's meteorological database consists of daily precipitation and temperature data from 141 U.S. Historical Climatology Network stations during 1976-2005. From that daily data the program calculates climate and crop evapotranspiration (ET_c) statistics over arbitrarily defined periods within summer or winter growing seasons at user-selected latitude-longitude coordinates. The statistics reported include: estimates of seasonal and sub-seasonal ET_c derived from the FAO-56 single crop coefficient algorithm, probabilities of exceedance of cumulative rainfall, irrigation demand and growing degree days, the probability that minimum and maximum daily temperatures will exceed user-defined temperature thresholds, and the probability of heat stress, cold stress and dry periods of varying duration.     

Development of the subsurface currents of the northern somali current gyre from march to july 1979

Measurements from March to July 1979 by current meters moored between the shelf and the deep sea from 5 degrees to 8 degrees N show that there was shallow ( < 150-meter) coastward and northward circulation between 6 degrees and 8 degrees N long before the onset of the southwest monsoon. After the onset, a powerful coastward flow developed offshore around 6 degrees N, branching into northward and southward flows at the continental rise while the current deepened to more than 250 meters. There seemed to be a separate circulation on the shelf with some counterflow to offshore. All current records show that there were strong fluctuations with periods of 3 to 6 days.     

气象条件与夏大豆生育进程和产量的相关分析

[目的]研究淮北地区气象条件对夏大豆(Glycine max)生长发育的影响,寻求影响其生长发育的关键因子。[方法]2011年设置46个品种(系)的展示试验,2004和2011年进行播期试验,同步观察夏大豆生长发育进程和气象因子。[结果]适期夏播中熟大豆播种～出苗5～6 d,需积温135～160℃;8～9片复叶展开时始花;出苗～始花27～35 d,需积温750～950℃;始花～成熟58～69 d,需积温1 350～1 600℃。生育期与主茎节数、有效分枝、单株结实荚数、荚粒数呈直线相关。播期推迟,生育期缩短,出苗～成熟所需积温减少,主茎节数减少,结实荚数下降,产量降低。夏大豆生长期内积温高、白昼时间长、≥0.1 mm雨日多,则产量高,生育期长;出苗～始花日照时数长,则始花推迟,主茎节数、单株粒数、产量增加;始花～成熟降水量多,则单株结实荚数、单株粒数和产量增加。[结论]淮北夏大豆应在6月中旬播种。     

内蒙古新巴尔虎左旗降水气候特征分析

根据1961~2010年新巴尔虎左旗国家基本气象站降水资料,采用线性趋势分析、重现期分析、变率分析、距平分析等方法,研究新巴尔虎左旗的降水特征。结果表明,50年来新巴尔虎左旗平均降水量为271.8 mm,年平均降水日数为140 d,年最大降水量590.5 mm年最小降水量125.7 mm,夏秋季降水较多,冬春季降水较少;新巴尔虎左旗50年的降水总体为波动中减少的趋势,降水总趋势以-0.69mm/10a变化率减少,春、冬季降水分别以0.60、0.90 mm/10a变化率增多,夏、秋季降水分别以-0.20、-0.18 mm/10a变化率减少。     

基于气象角度的济阳四季变化分析(英文)

[目的]从气象角度分析济阳四季变化特征,以期为该地区农事耕作和农业灾害防范提供参考依据。[方法]利用济阳地面气象观测站1981~2010年间的逐侯气温资料,从气象角度分析了济阳近30年四季开始时间和持续期的变化特点。[结果]近30年来,济阳春季和冬季开始时间呈现出提前的趋势,春季开始时间在四季中变化最为明显;夏季和秋季开始时间呈现出缓慢推迟的趋势,秋季开始时间变化较夏季开始时间变化明显。春季和冬季持续时间呈现出缩短的趋势,冬季持续时间较春季持续时间变化明显;夏季和秋季持续时间呈现出增长的趋势,夏季持续时间变化线性倾向率为0.042侯/年,在四季中变化最为明显。[结论]该研究结果显示在全球气候变暖的背景下,济阳四季的变化表现为夏季持续时间明显增长,春季和冬季持续时间缩短。     

Wheat Generation Adding in Xundian County of Yunnan Province in Summer

Local climate conditions and sowing time are very important to the vernalization and summer reproduction of the wheat. Xundian County is located in Yunnan Province of China, at latitude 25.56° north and longitude 103.25° east. Xundian County is situated 1 873 m above sea level, and is conducive for the summer reproduction of the wheat. To investigate the optimal sowing time, 11 spring wheat cultivars and one semi-winter wheat cultivar were sown 10 times at an interval of fi ve days from May 26, 2012, and the strong winter wheat Suyin 10 was treated in a vernalization room at 2℃ with different concentrations of the gibberellin and 5-azacytidine. The results showed that Suyin 10 should be vernalized at 2℃ for 30 days in summer, and the growth periods of strong winter wheat plants could been shortened if treated with a specifi c concentration of the gibberellin and 5-azacytidine at a low temperature. The growth period of the spring wheat in summer reproduction was delayed, and their agronomic traits gradually decreased with the passage of the sowing time. Thus, spring wheat should be sown at the earliest time possible for better yield. June 25 should be the latest date for summer reproduction of the wheat, but the semi-winter wheat cultivars in Xundian County should be added generation in summer after being treated at 2℃ for 10 days. Xundian County is a suitable location for summer reproduction of the wheat in China.     

天水市雷暴气候特征分析

为了研究天水市雷暴气候变化特征、周期性规律和时空分布特征,利用天水市7个观测站1971～2010年雷暴日资料,通过数理统计、Mann-Kendall检验、小波分析和EOF分析等方法分析近40年天水市雷暴气候特征。结果表明,天水市年平均雷暴日数为19.2 d,一年中雷暴发生在4～10月,7、8月份最多,雷暴主要发生在夏季;过去的40年,雷暴日数呈波动减少趋势,气候倾向率为-1.152d/10a;Mann-Kendall检验得出,在1995年天水雷暴日数开始明显减少,突变点出现在2008年,2008年后雷暴日数显著减少;Morlet小波分析结果表明,天水市雷暴日数同时存在3、6、12及22年的准周期变化;根据EOF分析,天水雷暴异常空间分布可划分为全市一致型和经向型,其中关山区雷暴日数最多,其次是渭北区,河谷区最少。     

近35年吴桥县夏玉米水分亏缺变化趋势分析

为探讨自然降雨和有限灌溉条件下提高夏玉米的产量和水分利用效率。本研究利用1981—2015年吴桥气象数据和SIMETAW模型,分析黑龙港流域夏玉米全生育期及播种-出苗、出苗-拔节期、拔节-吐丝期和吐丝-成熟期4个生育阶段的有效降水量、需水量、降水耦合度和水分亏缺指数(CWDI)的变化趋势,同时分析水分亏缺对夏玉米产量的影响。结果表明:1)近35年来夏玉米全生育期水分亏缺指数呈不显著下降趋势;降水耦合度呈不显著上升趋势;需水量呈显著上升趋势。生育期延长是夏玉米需水量上升的主导因素,30年来生育期延长20多天;2)夏玉米全生育期干旱程度主要为无旱和轻旱,概率分别为51.43%和45.71%,播种-苗期和吐丝-成熟期水分亏缺指数最高;3)一般年份,夏玉米需水量与降水耦合度高,降水基本能满足夏玉米生产;水分亏缺严重的年份,应在吐丝-成熟期补灌1次。     

Rapid eye movement sleep deprivation: a central-neural change during wakefulness

Three adult cats were deprived of rapid eye movement sleep for six separate periods of up to 32 days. Animals were allowed normal amouints of sleeping time during which rapid eye movement sleep was interrupted, whenever it occurred, by human observers who continually monitored the animals and their electrocortical activity. Cortical responses evoked by pairs of acoustic clicks were recorded during wakefulness. Recovery functions derived from these data were facilitated during periods of deprivation of rapid eye movement sleep and returned to base-line values when animals were allowed normal amounts of this sleep phase. This change was noted repeatedly within, as well as between, subjects. It did not occur during control periods when non-rapid eye movement sleep was interrupted on identical schedules, nor did it occur when the cats were deprived of all sleep for 22 hours a day for 5 days.     

湘南丘陵红壤持水特征及水分状况的研究

在湘南丘陵坡地第四纪红壤上连续定位测定土壤含水量,研究了湘南丘陵红壤的周年土壤水分状况。采用压力膜技术,测定了实验区红壤的土壤水分特征曲线,分析了红壤的持水和保水特征。结果表明：湘南丘陵第四纪红壤,质地粘重,水稳性微团聚体发育,持水性强,释水力差;湘南丘陵红壤区,降水丰富且季节性变化大,土壤含水量季节性变化明显。坡地红壤的土壤水分状况可划分为四个土壤水分时期：土壤潮湿期（冬-春季）、土壤水分耗损期（夏初）、土壤干旱期（夏季-秋初）和土壤水分补充恢复期（秋末）。湘南坡地红壤普遍存在季节性土壤干旱,多表现为夏秋连旱,对作物生产危害很大。文中还提出了旱地农业土壤水分调控原则。     

Phytoplankton division rates in light-limited environments: two adaptations

Red tide-forming dinoflagellates maximize cell numbers during periods of low light intensities in two ways. For short-term exposures to suboptimal light intensities such as might occur during recirculation in frontal convergences, cell division rates can be maintained at the expense of stored carbon for up to two generation times. During longer periods, corresponding to subsurface transport below a pycnocline, cell division rates eventually decrease as a portion of the fixed carbon is diverted to replenishing stored carbon. As a result, maximum rates of cell division can be resumed rapidly upon advection into surface waters where light intensities are optimal for growth.     

A Western boundary current in the gulf of Mexico

The curl of the wind stress over the Gulf of Mexico, during the winter and again in the summer, is similar to that over the central North Atlantic Ocean. An anticyclonic gyre is nearly always found in the western gulf, and we suggest that there is a typical western boundary current, similar in many important respects to the Gulf Stream. The flow appears to be strongest in winter and summer, in phase with the wind curl forcing, and there is evidence that this response is at least partially baroclinic. The deep baroclinic gyre persists when the wind curl vanishes. The winter transport is roughly half that of the Florida Current.     

An algorithm for temperature compensation in a heated greenhouse

A temperature compensation algorithm modifies the greenhouse heating setpoint depending on temperatures previously achieved. The algorithm increases the setpoint following a period when the heating is insufficient to achieve the blueprint temperature, and may also reduce the setpoint following a period of temperatures above the blueprint. The time constant used to calculate the average departure from the blueprint is long (1–10 days). Maximum compensation is obtained with a 10-day time constant. The correction applied to the blueprint varies very slowly and does not affect the rate of temperature change demanded during the dawn, evening, or dusk change over periods.     

江淮流域典型旱涝年夏季大气中的水汽输送和收支特征分析

利用NCEP/NCAR再分析资料对1994、1998年这2个典型旱涝年江淮流域水汽输送及收支状况等进行了诊断分析。结果表明,干旱年该地区主要为南北向水汽输送所控制,而洪涝年江淮流域上空有较强的东西向输送。干旱年5～8月由西、南边界的水汽输入明显比洪涝年少,是造成该地区旱涝的重要原因,因而在未来的江淮流域旱涝预测中要特别重视西、南边界的水汽输送。     

Nuclear winter: global consequences of multple nuclear explosions

The potential global atmospheric and climatic consequences of nuclear war are investigated using models previously developed to study the effects of volcanic eruptions. Although the results are necessarily imprecise due to wide range of possible scenaros and uncertainty in physical parameters, the most probable first-order effects are serious. Significant hemispherical attenuation of the solar radiation flux and subfreezing land temperatures may be caused by fine dust raised in high-yield nuclear surface bursts and by smoke from city and forest fires ignited by airbursts of all yields. For many simulated exchanges of several thousand megatons, in which dust and smoke are generated and encircle the earth within 1 to 2 weeks, average light levels can be reduced to a few percent of ambient and land temperatures can reach -15 degrees to -25 degrees C. The yield threshold for major optical and climatic consequences may be very low: only about 100 megatons detonated over major urban centers can create average hemispheric smoke optical depths greater than 2 for weeks and, even in summer, subfreezing land temperatures for months. In a 5000-megaton war, at northern mid-latitude sites remote from targets, radioactive fallout on time scales of days to weeks can lead to chronic mean doses of up to 50 rads from external whole-body gamma-ray exposure, with a likely equal or greater internal dose from biologically active radionuclides. Large horizontal and vertical temperature gradients caused by absorption of sunlight in smoke and dust clouds may greatly accelerate transport of particles and radioactivity from the Northern Hemisphere to the Southern Hemisphere. When combined with the prompt destruction from nuclear blast, fires, and fallout and the later enhancement of solar ultraviolet radiation due to ozone depletion, long-term exposure to cold, dark, and radioactivity could pose a serious threat to human survivors and to other species.