SWAT模型中的天气发生器对气象数据进行处理。

简介：
The pcpSTAT program, utilized for calculating statistical parameters required by the SWAT model’s meteorological generator (specifically the userwgn.dbf file), was developed by Stefan Liersch and released on August 12, 2003. Contact information: stliersch@freenet.de. The program’s downloadable location is available at http://www.brc.tamus.edu/swat/pcpSTAT.zip. This document details the usage of pcpSTAT.exe, focusing on the generation of daily precipitation data crucial for the SWAT model. Table 1 outlines several parameters readily calculable using tools like MICROSOFT EXCEL, while PR_W1 and PR_W2 present a greater computational challenge. Table 1 presents the precipitation statistical parameters employed within SWAT: PCPMM (mon) represents the average or mean total monthly precipitation; PCPSTD(mon) denotes the standard deviation for daily precipitation in a given month; PCPSKW(mon) indicates the skew coefficient for daily precipitation during that month; PR_W1(mon) signifies the probability of a wet day following a dry day; and PR_W2(mon) reflects the probability of a wet day following a wet day. Furthermore, PCPD(mon) quantifies the average number of days with precipitation recorded each month. The input files, containing daily precipitation data, must adhere to a specific format – an ASCII text file with a single column representing numerical values (illustrated in Figure 1). The observation period must commence on January 1st and conclude on December 31st of each year. Consequently, the initial data point corresponds to January 1st, while the final value represents December 31st. Although theres no restriction on total years utilized, each calculation should be based on an entire year’s worth of data. If missing data exists, it must be filled with blank values (represented as numeric characters). The program will prompt for these missing values, subsequently substituting them with the average value across the entire series. Figure 1 provides an example illustrating a suitable Precipitation Input File format. Creating an input file typically involves generating a text file where one column contains dates and another column holds corresponding precipitation values. Utilizing EXCEL to open this data file allows for date reduction if necessary, ensuring it begins with January 1st and concludes with December 31st of any year under consideration – after which date columns can be removed leaving only rainfall data which is then saved as text file (filename.txt). When utilizing alternative software or text editors to create or modify these files, it’s essential to maintain at least one blank line at the end to prevent operational errors during program execution; failure to do so may result in an error message End of file during read along with inaccurate output results.. Executing pcpSTAT.exe requires placing both the program and its input files within a shared directory; launching either by double-clicking pcpSTAT.exe or initiating it from a DOS window (as depicted in Figure 2). During execution, users are prompted to enter both input and output filenames including their respective extensions – naming conventions for output files are unrestricted.. Subsequently, users must input starting year followed by pressing Enter key to determine whether that year is leap year or not.. To indicate missing rainfall data points - non-existent numbers such as “999” should be entered as placeholders.. Following successful computation completion ,the output file (illustrated in Figure 3) is automatically saved within the programs directory alongside two supplementary files: totalpcp.sta and mean_pcp.sta . totalpcp .sta (Figure 4) contains yearly monthly totals while mean_pcp .sta presents yearly monthly averages of daily rainfall amounts .