西双版纳热带季节雨林干热季林冠上小气候特征及CO2通量的观测

热带森林在陆地生态系统中起着重要的作用,但是人们对它在碳循环中的作用却了解不多;近年来,为了对其进行深入研究,热带森林的CO2通量成为了研究的热点。应用微气象法中的开路系统涡度相关法,使用设置在西双版纳一片成熟的热带季节雨林中观测铁塔上的观测仪器所得的干热季7个晴好天气的CO2通量及小气候观测数据,对冠层的CO2通量及小气候特征进行了分析研究。研究结果表明:(1)热带季节雨林林冠上风速及摩擦风速在中午和上半夜较大,而后半夜和上午较小;风向有显著的昼、夜交替特征,昼间多为偏东风(45~135°),而夜间多为偏西风(250~280)°;(2)林冠上方气温和树冠面表温具有显著的日变化特征,树冠表温日变化幅度大于气温,热量由空气传向树冠中,在观测的7d中,气温有着较明显的升高趋势;(3)干热季林冠上湿度变化范围为26.5%~97.2%,饱和水汽压差数值大小介于0.3~30.5 hPa之间;(4)CO2浓度在364.5~408.5m l/m3之间变化,夜间浓度升高,而昼间CO2浓度降低;(5)地下5cm土壤温度与气温一样日变化规律明显,土壤含水量的变化幅度很小,在7d内其变化幅度维持在19.9%~23.3%之间,日变化幅度更小;(6)总体上讲林冠上方显热通量小于潜热通量,上午显热通量和潜热通量的数值基本相同,但是在中午和下午,潜热通量远大于显热通量,充分显示了西双版纳干热季热带雨林森林的热量支出主要是蒸腾耗热;(7)观测期间,生态系统净CO2交换(NEE)在-20.9~17.6μm o l/(m2.s)之间浮动,每天最大净CO2吸收速率在-20.9~-12.9μm o l/(m2.s)范围内。从生态系统净CO2交换的平均日变化看,昼间最大的净CO2吸收速率为-12.4μm o l/(m2.s),夜间最大的净释放速率为6.6μm o l/(m2.s)。净CO2交换的日累积量在-0.0665~0.0448m o l/m2范围内变化,7d的累积量为-0.0140 m o l/m2,表明在西双版纳干热季的7 d观测时间段里,热带季节雨林呈现弱的碳汇效应。     

西双版纳热带季节雨林林冠层温度与大气温度特征

根据2005年西双版纳热带季节雨林群落冠层植物表面温度以及林冠上、林冠下的气温资料,对热带季节雨林冠层温度和冠层气温及其之间的温度差异在不同季节的变化进行了分析。结果表明：热带季节雨林冠层温度除雾凉季夜间稍低于同层大气温度外,其他时间林冠温度皆高于同层大气温度,在雾凉季和干热季,热带季节雨林林冠上气温在大多数时刻高于林冠下气温;在中午前后林冠上气温低于林冠下气温。在平均温度较高的雨季,林冠上气温一直高于林冠下大气的温度;林冠上、林冠下气温之间的差异,显示西双版纳热带季节雨林林冠的生态效应对森林小气候的反馈作用;在雾凉季夜晚,热带季节雨林林冠温度与冠层气温与其他时间不同,雾凉季夜间低温是热带季节雨林能否存在的关键性限制因子。     

热带季节雨林林冠上方和林内近地层CO2浓度的时空动态及其成因分析

 为探讨西双版纳独特地方气候背景下,热带季节雨林CO₂浓度的时空变化特征和不同时间尺度上环境因素对森林CO₂浓度时间分布的作用,以及 为研究热带季节雨林的碳通量、净生态系统交换量(Net ecosystem exchange, NEE)等提供支持,我们利用热带季节雨林林冠上方和林内近地层 CO₂浓度连续监测资料,结合同步气象资料进行了统计分析。研究结果表明：在植被生理活动、土壤呼吸以及林内湍流的共同作用下,西双版纳 热带季节雨林CO₂浓度表现出明显的日变化、季节变化和林冠上下差异。在日尺度上,林冠上方的CO₂浓度时间变化曲线为“单峰型”,林内近 地层CO₂浓度时间变化曲线为“双峰型”,造成林内近地层傍晚第二个峰值的主要因子是地形因子作用下形成的局地环流。在季节尺度上,林冠 上方CO₂浓度主要受林冠代谢作用的影响,呈现雨季低、干季高的特点,而林内近地层的CO₂浓度则主要受地表呼吸过程所控制,季节变化趋势 与林冠上方相反。林冠上方CO₂浓度低于林内近地层CO₂浓度,且差异较大;在日尺度上,各月（除12月外）CO₂浓度的最大差值皆大于80 mg·m ^－3,且出现在傍晚;在季节尺度上,最大值为-62.9 mg·m^－3,出现在10月,最小值为-8.4 mg·m^－3,出现在12月。     

科尔沁草地不同大气稳定度下湍流特征谱分析

利用科尔沁半干旱风沙草原区涡度相关观测数据,计算并分析了不同大气稳定度条件下湍流的功率谱和协谱.结果表明:经向风速与纬向风速的功率谱在大气不稳定层结、近中性层结、稳定层结条件下谱形均相似,并遵循-2/3定律;近中性层结条件下垂直风速的功率谱没有惯性子区,此时仪器对脉动信号的捕捉不够完全,稳定层结条件下垂直风速功率谱表明观测层产生了泄流和平流;CO_2和H_2O浓度的功率谱分析表明,红外气体分析仪对高频信号的响应能力能够满足实际观测的需要,其功率谱的谱峰随大气稳定度的增强而向高频转移;垂直风速与3种标量的协谱谱形相似,不同大气稳定度下协谱惯性子区长度随大气稳定度的增强而变短,且均符合-4/3定律,说明三维超声风速仪与红外气体分析仪的空间间隔不会对通量观测结果造成显著影响.     

Gash模型在热带季节雨林林冠截留研究中的应用

为了验证Gash林冠截留解析模型在西双版纳热带季节雨林中的适用性,基于2003年的热带季节雨林气候及林冠特征观测数据、采用Gash模型对林冠截留进行了模拟.结果显示,西双版纳热带季节雨林样地年降雨量为1244.4mm,穿透降雨为867.3mm,树干径流为114.4mm,树冠截留量为262,7mm,林内穿透降雨量和林外降雨量之间存在显著的正相关关系;降雨过程中饱和林冠的蒸发强度为0.12mm/h,使林冠饱和的降雨为0.6mm,林冠枝叶部分持水能力为0.41mm,树干持水能力为0.18mm;模型模拟的年林冠截留量为274.9mm,干季为71.7 mm,雨季为203.1 mm;模拟的相对误差年值为4.3%,干季为0.1%,雨季为6.9%,模拟与实测有很好的一致性,显示了Gash模型适用于西双版纳地区热带季节雨林林冠截留计算.     

浓度的时空动态及其成因分析

为探讨西双版纳独特地方气候背景下,热带季节雨林CO₂浓度的时空变化特征和不同时间尺度上环境因素对森林CO₂浓度时间分布的作用,以及 为研究热带季节雨林的碳通量、净生态系统交换量(Net ecosystem exchange, NEE)等提供支持,我们利用热带季节雨林林冠上方和林内近地层 CO₂浓度连续监测资料,结合同步气象资料进行了统计分析。研究结果表明：在植被生理活动、土壤呼吸以及林内湍流的共同作用下,西双版纳 热带季节雨林CO₂浓度表现出明显的日变化、季节变化和林冠上下差异。在日尺度上,林冠上方的CO₂浓度时间变化曲线为“单峰型”,林内近 地层CO₂浓度时间变化曲线为“双峰型”,造成林内近地层傍晚第二个峰值的主要因子是地形因子作用下形成的局地环流。在季节尺度上,林冠 上方CO₂浓度主要受林冠代谢作用的影响,呈现雨季低、干季高的特点,而林内近地层的CO₂浓度则主要受地表呼吸过程所控制,季节变化趋势 与林冠上方相反。林冠上方CO₂浓度低于林内近地层CO₂浓度,且差异较大;在日尺度上,各月（除12月外）CO₂浓度的最大差值皆大于80 mg·m ^－3,且出现在傍晚;在季节尺度上,最大值为-62.9 mg·m^－3,出现在10月,最小值为-8.4 mg·m^－3,出现在12月。     

热带季节雨林和人工橡胶林林冠截留雾水的比较研究

利用 4a( 1 999～ 2 0 0 2 )的雾水截留观测资料 ,对西双版纳热带季节雨林和人工橡胶林林冠截留雾水进行了研究。热带季节雨林和人工橡胶林全年由林冠截留的雾水分别达 89.4± 1 3.5 mm和 1 8.6± 2 .5 mm(平均值±标准差 ) (雾季各占 62 .9%± 4.8%和 91 .9%± 6.3% ) ,分别占全年降水量的 4.9%± 1 .7%和1 .1 %± 0 .2 %。年雾水截留量与年降雨量呈负相关关系。月雾水截留量与月均最低气温呈显著的负相关 ,与月均相对湿度、月均 0∶ 0 0～ 1 0∶ 0 0风速呈显著的正相关。热带季节雨林全年 68%± 5 %、人工橡胶林40 %± 4%的有雾天气里可以收集到雾水 (分别为 0 .38± 0 .2 7mm/ d和 0 .2 4± 0 .1 2 mm/ d) ,且日雾水截留量与气温和风速呈显著的相关 ,即 :气温越低、风速越大 ,日雾水截留量越多。对本地区热带季节雨林生态系统的健康生长和维持而言 ,雾及雾水极大的弥补了降雨量的不足 ,雾的这种作用在降雨量少的年份似乎更为重要     

地形和历史干扰对西双版纳勐仑地区热带森林林冠高度结构的影响

以机载激光雷达为研究手段，结合1981和2021年的全色照片，利用多元回归树的方法对云南西双版纳国家级自然保护区勐仑子保护区的热带森林林冠高度结构及其与环境因子间的关系进行探讨。结果表明：勐仑子保护区西片森林可根据林冠高度结构差异而分为7类，其中包括热带季节雨林、季风常绿阔叶林、次生林和河漫滩林；潜在辐射强度、海拔、地形垂直曲率、坡度以及1981和2021年影像亮度平均值是影响林冠高度结构聚类的主要因子。以番龙眼为主要优势种的热带季节雨林在沟谷和低地地段占有最大的分布范围，而山脊和干扰迹地上则以短刺锥为优势种的季风常绿阔叶林为主。次生林地段林冠表面极为平整，结构上明显区别于天然林，30多年前的轮歇农业活动至今仍对森林外貌有着明显影响。     

西双版纳热带季雨林通量分配及能量平衡问题北大核心CSCD

为了探讨我国西双版纳热带季雨林的能量分配和平衡问题,利用涡度相关系统和常规气象仪器的连续监测结果,分析了不同季节的能量通量特征和闭合特点。结果表明,西双版纳热带季雨林全年的净辐射、潜热通量、显热通量、土壤热通量和热储存量分别是4546.07、2453.24、492.22、-10.47和45.93 MJ/m^(2),土壤为热源,潜热年总值占净辐射的54.0%,显热占10.8%,能量以蒸发散为主要的耗损形式。辐射和能量有明显的日变化和季节动态,各能量分量的日变化几乎都呈白天高夜间低的单峰趋势,反照率整体为0.10~0.12,波动不大;波文比季节差异明显,为0~0.8。热带季雨林的全年闭合度为0.67,未考虑热储量时,闭合度为0.51~0.79,考虑热储量为0.53~0.80。可见,在林冠茂密的热带季雨林中,热储量对能量闭合度的贡献不大,忽略热储量并不是导致能量不闭合的主要原因。     

西双版纳热带季节雨林风时空变化特征初步分析

利用西双版纳热带季节雨林观测铁塔不同高度的风速及风向观测资料,分析了风的年、季节和日变化特征.结果表明,林冠上风速较强,林冠下风速较弱;林内风速的日变化和垂直变化均不明显.30～50 m范围内,风速垂直变化最显著,但年变化不大;50 m以上风速年变化显著,但垂直变化稍小.干热季(3～4月)风速最大,雨季(5～10月)次之,雾凉季(11～翌年2月)最小.昼间风速大于夜间.在昼间,上午风速最小,下午次之,中午最大.受地理位置和地形影响,风向具有明显的日变化特征,主导风向昼间为偏东南风,夜间为偏西风.昼间零平面位移(d) 值上午最大,中午次之下午最小,其年变化幅度呈现下午幅度大,上午和中午幅度小的趋势.粗糙度(Z₀)昼间值呈现下午>中午>上午的趋势,且下午Z₀值显著大于其他两个时段.     

Comparative study of circadian variation in oral,tympanic, forehead,axillary and elbow pit temperatures measured in a cohort of young university students living their normal routines

The primary objective of the present research work is to study and compare the circadian variability in body temperature recorded from different locations of the body during subjects’ normal routines. Temperatures of oral cavity (sublingually), tympanum, forehead, axilla and the elbow pit were measured simultaneously at approximate 1-h intervals for five consecutive days during subjects’ waking span in their routine living condition. The observations were made in eight young, apparently healthy, university students. Data were analysed using cosinor rhythmometry for evaluation of circadian rhythms and two-way ANOVA with repeated measures to assess the effect of time of day and measuring site on body temperatures and their interaction. Significant circadian rhythms in body temperature, irrespective of site, were found. Based on autocorrelation analysis, it was observed that the day-to-day variability in body temperature was consistent. The acrophases of all the studied temperature rhythms were located in the afternoon, except axillary temperature, which occurred in the early evening. The mean daytime temperature was found to be the highest when recorded sublingually and it was the lowest on the forehead or elbow pit. On the basis of the results of this study, we recommend that the methods used could be introduced into laboratory courses in a curriculum of chronobiology courses for both UG and PG classes for the demonstration/study of circadian rhythms in body temperature under normal routines. The methods used are valuable as they are non-invasive, easily accepted and assessable in a student setting.     

灰飞虱发育起点温度及有效积温的探讨

利用培养箱在恒温条件下饲养灰飞虱Laodelphax striatellus Fallén,测定了卵、若虫、成虫繁殖前和全世代发育历期,用直线回归法计算了灰飞虱各虫态和全世代的发育起点温度和有效积温分别为10.06、6.43、10.29、8.08℃和102.3、365.2、87.5、552.1日·度。并根据有效积温法则预测了该虫在济宁市1年完成的代数为4～5代。     

桑树(Morus alba)朱砂叶螨（Tetranychus cinnabarinus）实验种群的温度效应

采用生命表分析、生存分析、"王-兰-丁"模型及线性模型等分析方法,对15～28℃温区的5个恒温处理朱砂叶螨(Tetranychus cinnabarinus)实验种群进行了系统研究.结果表明,此温区内,种群在生殖、发育和生存3方面,有明显的温度效应:内禀增长力、周限增长力、净增殖力和平均日产卵量、世代平均周期、及种群倍增时间的倒数呈线性增长;而平均寿命、最大死亡年龄,随温度升高而递减;性比和实际产卵天数对温度不敏感.种群在生殖、发育和生存三者之间,采取了较为"折衷"的策略:8℃为发育临界点;13℃左右为生殖和种群增长临界温度;22℃左右为生殖和种群增长最适温度;30℃左右为发育最适温度.     

竹织叶野螟发育起点温度和有效积温

采用19,22,25,28和31℃5个温度对竹织叶野螟Algedonia coclesalis Walker各虫态(龄)发育起点温度和有效积温进行测定。结果表明,竹织叶野螟的在19～31℃范围内均能正常生长发育,尤其是28～31℃范围最适宜于竹织叶野螟的生长发育。卵、1龄幼虫、2龄幼虫、3龄幼虫、4龄幼虫、5龄幼虫、6龄幼虫、7龄幼虫、蛹、成虫及世代的发育起点温度分别为6.63,12.51,11.18,10.93,10.05,8.01,6.80,5.78,6.20,7.81和8.33℃,有效积温分别为124.19,64.54,72.59,82.08,93.46,136.84,155.42,201.06,211.55,111.49和1235.50日.度。     

核桃扁叶甲的发育起点温度和有效积温

室内观察测定5个恒温条件下,核桃扁叶甲Gastrolina depressa Baly各虫态的发育历期及起点温度和有效积温。结果表明:在16～32℃温度范围内,核桃扁叶甲均能完成发育,其发育历期随温度的升高而缩短,卵期、幼虫期、蛹期、产卵前期的发育起点温度分别为9.4,12.2,14.3和11.1℃,有效积温分别为43.2,77.2,36.0和104.7日.度;整个世代的发育起点温度为12.0℃,有效积温为260.5日.度。持续过高温度不适合核桃扁叶甲的生长发育。     

Evaluation of the cold strain index (CSI) for peripheral cold environmental stress

The purpose of this study was to evaluate the cold strain index (CSI) for peripheral environmental stress using data from a previous footwear study. Eight men (20±2 yr) dressed in protective cold weather clothing with varying footwear underwent 5 days of cold air (−23.4 °C) testing while attempting to sit for 240 min. Rectal, skin, and toe temperatures (T_toe) were continuously measured. All test exposures were ended after 50–165 min due to cold foot discomfort or T_toe<5 °C. However, CSI values indicated little cold strain. Therefore, we revised CSI to include peripheral cold assessment, which was found to be consistent with subject behavior and measured low T_toe.     

恒温下大戟长管蚜的发育起点温度和有效积温

在16,19,22,25,28和31℃恒温条件下以花卉一串红(Salvia splendens)饲养大戟长管蚜Macrosiphum euphorbiae(Thomas),测得该蚜虫的各龄历期和产仔前期,得出全若虫期的历期。依据有效积温法则计算的1～4龄若蚜和全若虫期的发育起点分别是12.5,7.8,10.3,4.1和9.3℃,有效积温分别是14.6,43.9,29.9,31.9和117.2日.度。大戟长管蚜适合生长发育的温度是19～28℃,最适合温度为25℃。     

Considerations for the measurement of core,skin and mean body temperatures

Despite previous reviews and commentaries, significant misconceptions remain concerning deep-body (core) and skin temperature measurement in humans. Therefore, the authors have assembled the pertinent Laws of Thermodynamics and other first principles that govern physical and physiological heat exchanges. The resulting review is aimed at providing theoretical and empirical justifications for collecting and interpreting these data. The primary emphasis is upon deep-body temperatures, with discussions of intramuscular, subcutaneous, transcutaneous and skin temperatures included. These are all turnover indices resulting from variations in local metabolism, tissue conduction and blood flow. Consequently, inter-site differences and similarities may have no mechanistic relationship unless those sites have similar metabolic rates, are in close proximity and are perfused by the same blood vessels. Therefore, it is proposed that a gold standard deep-body temperature does not exist. Instead, the validity of each measurement must be evaluated relative to one's research objectives, whilst satisfying equilibration and positioning requirements. When using thermometric computations of heat storage, the establishment of steady-state conditions is essential, but for clinically relevant states, targeted temperature monitoring becomes paramount. However, when investigating temperature regulation, the response characteristics of each temperature measurement must match the forcing function applied during experimentation. Thus, during dynamic phases, deep-body temperatures must be measured from sites that track temperature changes in the central blood volume.     

Development of a self-contained,indwelling vaginal temperature probe for use in cattle research

A device was developed to monitor the vaginal temperature of cattle in a research setting. This device decreases labor involved with monitoring body temperature compared with manual temperature readings, allows for continuous monitoring of vaginal temperature at 1 min intervals, and also allows for temperature measurements without the presence of a human handler or without restraint, which can agitate cattle. The device consists of a blank controlled internal drug release (CIDR) device (designed by Pfizer Animal Health as an indwelling vaginal probe) that holds an indwelling vaginal temperature probe logger. The fabrication of the vaginal probe costs approximately US $325 per unit. Similar rectal and vaginal temperature responses to lipopolysaccharide challenge were observed when vaginal and rectal temperatures were measured simultaneously in the same heifer (P>0.05). Additionally, rectal and vaginal temperatures were highly correlated (r=0.97; P<0.0001). Similar to the rectal temperature monitoring device, the vaginal device allows for the measurement of vaginal temperature without the potential biases associated with the stress response produced as a reaction to the handling by and (or) presence of humans. The vaginal temperature recording device will provide researchers with an additional inexpensive tool to study physiological responses in female cattle.     

A study of human skin and surface temperatures in stable and unstable thermal environments

Skin temperature is a common physiological parameter that reflects human thermal responses. The purpose of this research was to investigate the effects of radiant temperature on human skin temperature and surface temperature in stable and unstable thermal environments. For a clothed human body, the skin temperature is the surface temperature of the skin, while the surface temperature is the outer surface temperature of the clothes. For this aim, the radiant temperature from 26 to 38 °C and then from 38 to 26 °C was controlled in three different ways; in stable condition keeping stable above 40 min, in unstable condition at a rate of 2 °C/5 min, and in another unstable condition at a rate of 2 °C/10 min. Experimental data showed that at the same radiant temperature, the local skin/surface temperatures during the radiant temperature decrease were higher compared to those during the radiant temperature increase. During the radiant temperature increase/decrease, the increments/decrements of the mean skin temperature and the mean surface temperature decreased gradually from the stable condition, 2 °C/10 min to 2 °C/5 min. Compared to surface temperature, the faster the radiant temperature changed, the more obviously the change in skin temperature was delayed. These data demonstrated that the human body has physiological adaptability to unstable thermal environments.