pvlib.tmy.readtmy2

pvlib.tmy.readtmy2(filename)

Deprecated since version 0.6.1: The readtmy2 function was deprecated in pvlib 0.6.1 and will be removed in 0.7. Use iotools.read_tmy2 instead.

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.