pvlib.tmy.readtmy2¶
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pvlib.tmy.
readtmy2
(filename)[source]¶ Read a TMY2 file in to a DataFrame.
Note that values contained in the DataFrame are unchanged from the TMY2 file (i.e. units are retained). Time/Date and location data imported from the TMY2 file have been modified to a “friendlier” form conforming to modern conventions (e.g. N latitude is postive, E longitude is positive, the “24th” hour of any day is technically the “0th” hour of the next day). In the case of any discrepencies between this documentation and the TMY2 User’s Manual [1], the TMY2 User’s Manual takes precedence.
Parameters: - filename : None or string
If None, attempts to use a Tkinter file browser. A string can be a relative file path, absolute file path, or url.
Returns: - Tuple of the form (data, metadata).
- data : DataFrame
A dataframe with the columns described in the table below. For a more detailed descriptions of each component, please consult the TMY2 User’s Manual ([1]), especially tables 3-1 through 3-6, and Appendix B.
- metadata : dict
The site metadata available in the file.
Notes
The returned structures have the following fields.
key description WBAN Site identifier code (WBAN number) City Station name State Station state 2 letter designator TZ Hours from Greenwich latitude Latitude in decimal degrees longitude Longitude in decimal degrees altitude Site elevation in meters TMYData field description index Pandas timeseries object containing timestamps year month day hour ETR Extraterrestrial horizontal radiation recv’d during 60 minutes prior to timestamp, Wh/m^2 ETRN Extraterrestrial normal radiation recv’d during 60 minutes prior to timestamp, Wh/m^2 GHI Direct and diffuse horizontal radiation recv’d during 60 minutes prior to timestamp, Wh/m^2 GHISource See [1], Table 3-3 GHIUncertainty See [1], Table 3-4 DNI Amount of direct normal radiation (modeled) recv’d during 60 mintues prior to timestamp, Wh/m^2 DNISource See [1], Table 3-3 DNIUncertainty See [1], Table 3-4 DHI Amount of diffuse horizontal radiation recv’d during 60 minutes prior to timestamp, Wh/m^2 DHISource See [1], Table 3-3 DHIUncertainty See [1], Table 3-4 GHillum Avg. total horizontal illuminance recv’d during the 60 minutes prior to timestamp, units of 100 lux (e.g. value of 50 = 5000 lux) GHillumSource See [1], Table 3-3 GHillumUncertainty See [1], Table 3-4 DNillum Avg. direct normal illuminance recv’d during the 60 minutes prior to timestamp, units of 100 lux DNillumSource See [1], Table 3-3 DNillumUncertainty See [1], Table 3-4 DHillum Avg. horizontal diffuse illuminance recv’d during the 60 minutes prior to timestamp, units of 100 lux DHillumSource See [1], Table 3-3 DHillumUncertainty See [1], Table 3-4 Zenithlum Avg. luminance at the sky’s zenith during the 60 minutes prior to timestamp, units of 10 Cd/m^2 (e.g. value of 700 = 7,000 Cd/m^2) ZenithlumSource See [1], Table 3-3 ZenithlumUncertainty See [1], Table 3-4 TotCld Amount of sky dome covered by clouds or obscuring phenonema at time stamp, tenths of sky TotCldSource See [1], Table 3-5, 8760x1 cell array of strings TotCldUnertainty See [1], Table 3-6 OpqCld Amount of sky dome covered by clouds or obscuring phenonema that prevent observing the sky at time stamp, tenths of sky OpqCldSource See [1], Table 3-5, 8760x1 cell array of strings OpqCldUncertainty See [1], Table 3-6 DryBulb Dry bulb temperature at the time indicated, in tenths of degree C (e.g. 352 = 35.2 C). DryBulbSource See [1], Table 3-5, 8760x1 cell array of strings DryBulbUncertainty See [1], Table 3-6 DewPoint Dew-point temperature at the time indicated, in tenths of degree C (e.g. 76 = 7.6 C). DewPointSource See [1], Table 3-5, 8760x1 cell array of strings DewPointUncertainty See [1], Table 3-6 RHum Relative humidity at the time indicated, percent RHumSource See [1], Table 3-5, 8760x1 cell array of strings RHumUncertainty See [1], Table 3-6 Pressure Station pressure at the time indicated, 1 mbar PressureSource See [1], Table 3-5, 8760x1 cell array of strings PressureUncertainty See [1], Table 3-6 Wdir Wind direction at time indicated, degrees from east of north (360 = 0 = north; 90 = East; 0 = undefined,calm) WdirSource See [1], Table 3-5, 8760x1 cell array of strings WdirUncertainty See [1], Table 3-6 Wspd Wind speed at the time indicated, in tenths of meters/second (e.g. 212 = 21.2 m/s) WspdSource See [1], Table 3-5, 8760x1 cell array of strings WspdUncertainty See [1], Table 3-6 Hvis Distance to discernable remote objects at time indicated (7777=unlimited, 9999=missing data), in tenths of kilometers (e.g. 341 = 34.1 km). HvisSource See [1], Table 3-5, 8760x1 cell array of strings HvisUncertainty See [1], Table 3-6 CeilHgt Height of cloud base above local terrain (7777=unlimited, 88888=cirroform, 99999=missing data), in meters CeilHgtSource See [1], Table 3-5, 8760x1 cell array of strings CeilHgtUncertainty See [1], Table 3-6 Pwat Total precipitable water contained in a column of unit cross section from Earth to top of atmosphere, in millimeters PwatSource See [1], Table 3-5, 8760x1 cell array of strings PwatUncertainty See [1], Table 3-6 AOD The broadband aerosol optical depth (broadband turbidity) in thousandths on the day indicated (e.g. 114 = 0.114) AODSource See [1], Table 3-5, 8760x1 cell array of strings AODUncertainty See [1], Table 3-6 SnowDepth Snow depth in centimeters on the day indicated, (999 = missing data). SnowDepthSource See [1], Table 3-5, 8760x1 cell array of strings SnowDepthUncertainty See [1], Table 3-6 LastSnowfall Number of days since last snowfall (maximum value of 88, where 88 = 88 or greater days; 99 = missing data) LastSnowfallSource See [1], Table 3-5, 8760x1 cell array of strings LastSnowfallUncertainty See [1], Table 3-6 PresentWeather See [1], Appendix B, an 8760x1 cell array of strings. Each string contains 10 numeric values. The string can be parsed to determine each of 10 observed weather metrics. References
[1] Marion, W and Urban, K. “Wilcox, S and Marion, W. “User’s Manual for TMY2s”. NREL 1995.