Help on function read_tmy3 in module pvlib.iotools.tmy:
+
+read_tmy3(filename, coerce_year=None, recolumn=True)
+ Read a TMY3 file in to a pandas dataframe.
+
+ Note that values contained in the metadata dictionary are unchanged
+ from the TMY3 file (i.e. units are retained). In the case of any
+ discrepancies between this documentation and the TMY3 User's Manual
+ [1]_, the TMY3 User's Manual takes precedence.
+
+ The TMY3 files were updated in Jan. 2015. This function requires the
+ use of the updated files.
+
+ Parameters
+ ----------
+ filename : str
+ A relative file path or absolute file path.
+
+ coerce_year : None or int, default None
+ If supplied, the year of the index will be set to `coerce_year`, except
+ for the last index value which will be set to the *next* year so that
+ the index increases monotonically.
+
+ recolumn : bool, default True
+ If ``True``, apply standard names to TMY3 columns. Typically this
+ results in stripping the units from the column name.
+
+ Returns
+ -------
+ Tuple of the form (data, metadata).
+
+ data : DataFrame
+ A pandas dataframe with the columns described in the table
+ below. For more detailed descriptions of each component, please
+ consult the TMY3 User's Manual ([1]), especially tables 1-1
+ through 1-6.
+
+ metadata : dict
+ The site metadata available in the file.
+
+ Notes
+ -----
+ The returned structures have the following fields.
+
+ =============== ====== ===================
+ key format description
+ =============== ====== ===================
+ altitude Float site elevation
+ latitude Float site latitudeitude
+ longitude Float site longitudeitude
+ Name String site name
+ State String state
+ TZ Float UTC offset
+ USAF Int USAF identifier
+ =============== ====== ===================
+
+ ============================= ======================================================================================================================================================
+ TMYData field description
+ ============================= ======================================================================================================================================================
+ TMYData.Index A pandas datetime index. NOTE, the index is currently timezone unaware, and times are set to local standard time (daylight savings is not included)
+ TMYData.ETR Extraterrestrial horizontal radiation recv'd during 60 minutes prior to timestamp, Wh/m^2
+ TMYData.ETRN Extraterrestrial normal radiation recv'd during 60 minutes prior to timestamp, Wh/m^2
+ TMYData.GHI Direct and diffuse horizontal radiation recv'd during 60 minutes prior to timestamp, Wh/m^2
+ TMYData.GHISource See [1]_, Table 1-4
+ TMYData.GHIUncertainty Uncertainty based on random and bias error estimates see [2]_
+ TMYData.DNI Amount of direct normal radiation (modeled) recv'd during 60 mintues prior to timestamp, Wh/m^2
+ TMYData.DNISource See [1]_, Table 1-4
+ TMYData.DNIUncertainty Uncertainty based on random and bias error estimates see [2]_
+ TMYData.DHI Amount of diffuse horizontal radiation recv'd during 60 minutes prior to timestamp, Wh/m^2
+ TMYData.DHISource See [1]_, Table 1-4
+ TMYData.DHIUncertainty Uncertainty based on random and bias error estimates see [2]_
+ TMYData.GHillum Avg. total horizontal illuminance recv'd during the 60 minutes prior to timestamp, lx
+ TMYData.GHillumSource See [1]_, Table 1-4
+ TMYData.GHillumUncertainty Uncertainty based on random and bias error estimates see [2]_
+ TMYData.DNillum Avg. direct normal illuminance recv'd during the 60 minutes prior to timestamp, lx
+ TMYData.DNillumSource See [1]_, Table 1-4
+ TMYData.DNillumUncertainty Uncertainty based on random and bias error estimates see [2]_
+ TMYData.DHillum Avg. horizontal diffuse illuminance recv'd during the 60 minutes prior to timestamp, lx
+ TMYData.DHillumSource See [1]_, Table 1-4
+ TMYData.DHillumUncertainty Uncertainty based on random and bias error estimates see [2]_
+ TMYData.Zenithlum Avg. luminance at the sky's zenith during the 60 minutes prior to timestamp, cd/m^2
+ TMYData.ZenithlumSource See [1]_, Table 1-4
+ TMYData.ZenithlumUncertainty Uncertainty based on random and bias error estimates see [1]_ section 2.10
+ TMYData.TotCld Amount of sky dome covered by clouds or obscuring phenonema at time stamp, tenths of sky
+ TMYData.TotCldSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.TotCldUncertainty See [1]_, Table 1-6
+ TMYData.OpqCld Amount of sky dome covered by clouds or obscuring phenonema that prevent observing the sky at time stamp, tenths of sky
+ TMYData.OpqCldSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.OpqCldUncertainty See [1]_, Table 1-6
+ TMYData.DryBulb Dry bulb temperature at the time indicated, deg C
+ TMYData.DryBulbSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.DryBulbUncertainty See [1]_, Table 1-6
+ TMYData.DewPoint Dew-point temperature at the time indicated, deg C
+ TMYData.DewPointSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.DewPointUncertainty See [1]_, Table 1-6
+ TMYData.RHum Relatitudeive humidity at the time indicated, percent
+ TMYData.RHumSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.RHumUncertainty See [1]_, Table 1-6
+ TMYData.Pressure Station pressure at the time indicated, 1 mbar
+ TMYData.PressureSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.PressureUncertainty See [1]_, Table 1-6
+ TMYData.Wdir Wind direction at time indicated, degrees from north (360 = north; 0 = undefined,calm)
+ TMYData.WdirSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.WdirUncertainty See [1]_, Table 1-6
+ TMYData.Wspd Wind speed at the time indicated, meter/second
+ TMYData.WspdSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.WspdUncertainty See [1]_, Table 1-6
+ TMYData.Hvis Distance to discernable remote objects at time indicated (7777=unlimited), meter
+ TMYData.HvisSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.HvisUncertainty See [1]_, Table 1-6
+ TMYData.CeilHgt Height of cloud base above local terrain (7777=unlimited), meter
+ TMYData.CeilHgtSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.CeilHgtUncertainty See [1]_, Table 1-6
+ TMYData.Pwat Total precipitable water contained in a column of unit cross section from earth to top of atmosphere, cm
+ TMYData.PwatSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.PwatUncertainty See [1]_, Table 1-6
+ TMYData.AOD The broadband aerosol optical depth per unit of air mass due to extinction by aerosol component of atmosphere, unitless
+ TMYData.AODSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.AODUncertainty See [1]_, Table 1-6
+ TMYData.Alb The ratio of reflected solar irradiance to global horizontal irradiance, unitless
+ TMYData.AlbSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.AlbUncertainty See [1]_, Table 1-6
+ TMYData.Lprecipdepth The amount of liquid precipitation observed at indicated time for the period indicated in the liquid precipitation quantity field, millimeter
+ TMYData.Lprecipquantity The period of accumulatitudeion for the liquid precipitation depth field, hour
+ TMYData.LprecipSource See [1]_, Table 1-5, 8760x1 cell array of strings
+ TMYData.LprecipUncertainty See [1]_, Table 1-6
+ TMYData.PresWth Present weather code, see [2]_.
+ TMYData.PresWthSource Present weather code source, see [2]_.
+ TMYData.PresWthUncertainty Present weather code uncertainty, see [2]_.
+ ============================= ======================================================================================================================================================
+
+ .. warning:: TMY3 irradiance data corresponds to the *previous* hour, so
+ the first index is 1AM, corresponding to the irradiance from midnight
+ to 1AM, and the last index is midnight of the *next* year. For example,
+ if the last index in the TMY3 file was 1988-12-31 24:00:00 this becomes
+ 1989-01-01 00:00:00 after calling :func:`~pvlib.iotools.read_tmy3`.
+
+ .. warning:: When coercing the year, the last index in the dataframe will
+ become midnight of the *next* year. For example, if the last index in
+ the TMY3 was 1988-12-31 24:00:00, and year is coerced to 1990 then this
+ becomes 1991-01-01 00:00:00.
+
+ References
+ ----------
+
+ .. [1] Wilcox, S and Marion, W. "Users Manual for TMY3 Data Sets".
+ NREL/TP-581-43156, Revised May 2008.
+
+ .. [2] Wilcox, S. (2007). National Solar Radiation Database 1991 2005
+ Update: Users Manual. 472 pp.; NREL Report No. TP-581-41364.
+