Wind speed data for shore and forest on an island in French Polynesia

Wind data were collected on three days during the second and third weeks of June in 2010 on Motu Tiahura when the weather was clear or partly cloudy and calm. The two sites for collection were the "shore" on open sand approximately 3 meters inland from the high-tide mark and at least 3 meters from the beginning of the tree line and "forest" on the leaf-litter under tree canopy at least 10 meters from the tree line. Hermit crabs were collected from both sites where wind data were collected. Wind speed measurements were collected using a hot-wire anemometer (Kurz 443M, Kurz Instruments, Inc, Monterey, CA) in a water-proof casing. Data was routed through a DAQ card (National Instruments, Inc., Austin, TX) to a Matlab software acquisition GUI on an IBM Thinkpad laptop. The anemometer was calibrated in a wind tunnel across a wide range of wind speeds prior to being taken into the field. Data were collected at 12 heights above the substratum from 5 mm to 0.68 m, covering the height range which hermit crabs would likely capture odors. Wind speeds were sampled at data were taken for three-minute intervals and sampled at 100 Hz. Measurements were repeated three times (on three different days) and averaged for each position above the substratum. Turbulence intensity was calcuated by dividing the standard deviation of wind speed in the sample by the mean speed of the sample. Statistics were performed with R and values are reported with standard error. Mean_vel.pdf reports wind speeds (in meters per second) graphed against height above substratum (in meters). Red dots indicate the "forest" location and blue dots indicate "shore" location. In a linear regression model (speed~height*location), there is a significant correlation between speed and height above substratum (slope = 0.18 ±0.04, t-value = 4.477, dof = 20, p = 2e-4) but only a slight correlation between speed and location (coef = 0.0506 ±0.02, t-value = 2.252, dof = 20, p = 0.03). turbint_regression.pdf reports turbulence intensities graphed against height above substratum (in meters). In a linear regression model (turbulence intensity~height*location), turbulence intensity has a significant correlation with height above substratum (slope = 0.0845 ±0.01, t-value = 5.712, dof = 20, p = 1e-5) but no relationship with location (coef = -0.00851 ±0.008, t-value = -1.07, dof = 20, p = 0.30).

2010年6月第二、三周，在莫图蒂阿乌拉（Motu Tiahura），于晴朗、少云且风力平稳的天气下，连续三日采集了风速数据。本次风速采集共设两个站点：其一为"岸基站点"，位于距高潮线约3米的开阔沙地，且与林缘间距至少3米；其二为"林内站点"，位于林缘至少10米外的树冠下枯落物区域。两个风速采集站点均同步采集了寄居蟹样本。风速测量采用带防水外壳的热线风速仪（hot-wire anemometer，Kurz 443M，Kurz Instruments公司，加利福尼亚州蒙特雷），采集数据通过数据采集卡（DAQ card，National Instruments公司，得克萨斯州奥斯汀）传输至IBM Thinkpad笔记本电脑上的Matlab软件采集图形用户界面（GUI）。该热线风速仪在野外部署前，已在风洞中针对宽范围风速区间完成校准。数据采集覆盖距基底0.005米至0.68米的12个高度层级，该高度区间覆盖了寄居蟹感知气味的典型高度范围。采样以3分钟为一个采集周期，采样频率设为100Hz。每个基底高度处的测量均重复三次（分三日完成），最终取三次测量的平均值。湍流强度通过将单次采样内风速的标准差除以该采样的平均风速计算得到。所有统计分析均通过R语言完成，结果以标准误形式报告。文件Mean_vel.pdf展示了以基底上方高度（单位：米）为横轴、风速（单位：米每秒）为纵轴的散点图，其中红色圆点代表"林内站点"，蓝色圆点代表"岸基站点"。在线性回归模型（风速~高度*站点类型）中，风速与基底上方高度存在显著相关性（斜率=0.18±0.04，t值=4.477，自由度=20，p=2e-4），而风速与站点类型仅存在微弱相关性（系数=0.0506±0.02，t值=2.252，自由度=20，p=0.03）。文件turbint_regression.pdf展示了以基底上方高度（单位：米）为横轴的湍流强度散点图。在线性回归模型（湍流强度~高度*站点类型）中，湍流强度与基底上方高度存在显著相关性（斜率=0.0845±0.01，t值=5.712，自由度=20，p=1e-5），但与站点类型无显著关联（系数=-0.00851±0.008，t值=-1.07，自由度=20，p=0.30）。