Evapotranspiration Data

A regional evaluation of evapotranspiration (ET) in the Florida Everglades began in 1996 with operation of 9 sites at locations selected to represent the sawgrass or cattail marshes, wet prairie, and open-water areas that constitute most of the natural Everglades system. The Bowen-ratio energy-budget method was used to measure ET at 30-minute intervals. Site models were developed to determine ET for intervals when a Bowen ratio could not be accurately determined. Regional models were then developed for determining 30-minute ET at any location as a function of solar intensity and water depth using data from the 9 sites for 1996-97. Five of the original 9 sites continued in operation after 1997 for various periods. Two of these sites were operated continuously until September 2003. Three new sites were installed in the western part of Shark Valley in November 2001 for the purpose of testing regional model transferability. Additionally, an evaporation pan was installed at one site in April 2001 for comparing actual ET determined by the Bowen-ratio site with potential pan evaporation. All data collection ended in September 2003. The dataset contains the meteorological and evapotranspiration data. Additionally, tables listing model coefficients and goodness-of-fit statistics for site models for the period 1998-2003 are included, and tables listing a comparison for measured ET and ET estimated from the regional models. Data is available by year for each of the collection sites. The a_read_me file in the Data summary and data files for Everglades ET sites, 1996-2003 describes the format of data files of meteorological and evapotranspiration data. Additionally, tables listing model coefficients and goodness-of-fit statistics for site models for the period 1998-2003 are included, and tables listing a comparison for measured ET and ET estimated from the regional models. This latest data release is different in format from the original release for all data from 1998 on. No changes were made in the 1996-97 data. One change made in reporting format is that ET data from 1998 on are not smoothed by averaging over one or more measurement intervals. With this release data are provided at the measurement interval so that users may use whatever smoothing technique that is appropriate for the intended use. Another change in format for data from 1998 on is that ET sums are provided for "raw" and "edited" 30-minute periods. The "raw" data refer to ET sums that have not been edited from computed results, although the ET sum may be an actual measurement that has passed all input-data screening tests (see WRI 00-4217), or may be a "gap-filled" value computed from the Priestley-Taylor site mode that was developed using only data that passed all screening tests. Data in the "edited" column have been edited graphically by comparing each value to the pattern of ET defined by the entire set of data during part of a day. The final change in format for data from 1998 on is that a flag indicator is provided to show which 30-minute ET data are measured and which are model derived because the input data did not pass screening criteria.1996年，佛罗里达大沼泽地（Florida Everglades）蒸散量（evapotranspiration, ET）区域评估项目正式启动，首批在代表该自然生态系统核心组成的锯草/香蒲沼泽、湿草原及开阔水域区域布设9个监测站点并投入运行。研究采用波文比能量平衡法（Bowen-ratio energy-budget method），以30分钟为间隔开展ET观测。针对无法精准获取波文比的时段，研究人员构建了站点尺度模型以推算ET；随后基于1996至1997年9个站点的观测数据，进一步构建区域尺度模型，可通过太阳辐射强度与水深两个变量，推算任意点位的30分钟间隔ET值。 1997年后，初始9个站点中有5个仍持续运行，运行时长各有差异。其中2个站点连续运行至2003年9月。2001年11月，研究团队在鲨鱼谷（Shark Valley）西部新增3个监测站点，用于验证区域模型的可迁移性。此外，2001年4月在1个站点布设蒸发皿（evaporation pan），用于对比波文比法实测ET与蒸发器潜在蒸发量。所有数据采集工作于2003年9月正式终止。本数据集涵盖气象数据与蒸散量数据，同时收录1998至2003年站点模型的系数表、拟合优度统计量表，以及实测ET与区域模型估算ET的对比表。 数据可按年份从各采集站点获取。 本数据集附带的《1996-2003年大沼泽地ET站点数据摘要与数据文件》中的a_read_me文件，详细说明了气象与蒸散量数据文件的格式。此外，数据集还包含1998至2003年站点模型的系数表、拟合优度统计量表，以及实测ET与区域模型估算ET的对比表。 本次最新发布的数据，与1998年及以后的原始发布数据格式存在差异；1996至1997年的数据未做任何修改。 报告格式的一项调整为：1998年及以后的ET数据不再通过对单个或多个观测时段取平均的方式进行平滑处理。本次发布的数据保留原始观测间隔，使用者可根据实际应用需求选择合适的平滑处理方法。 1998年及以后的数据格式另一项调整为：提供“原始”与“已编辑”两类30分钟时段的ET累加值。“原始”数据指未经过计算结果编辑的ET累加值，这类数据既可能是通过了所有输入数据筛选测试的实测值（参见WRI 00-4217），也可能是基于仅使用通过筛选测试的数据构建的Priestley-Taylor站点模型生成的间隙填充值。“已编辑”列的数据则通过将每个值与当日部分时段内的全量ET数据模式进行对比，经图形化编辑得到。 1998年及以后的数据格式最后一项调整为：新增标记指示器，用于标识哪些30分钟ET数据为实测值，哪些因输入数据未通过筛选标准而采用模型推算值。