pvlib.iotools.read_tmy2#

pvlib.iotools.read_tmy2(filename)[source]#

Read a TMY2 file into 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 (str) – A relative or absolute file path.

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

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
TotCldUncertainty	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
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
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
DewPointUncertainty	See [1], Table 3-6
RHum	Relative humidity at the time indicated, percent
RHumSource	See [1], Table 3-5
RHumUncertainty	See [1], Table 3-6
Pressure	Station pressure at the time indicated, 1 mbar
PressureSource	See [1], Table 3-5
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
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
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
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
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
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
AODUncertainty	See [1], Table 3-6
SnowDepth	Snow depth in centimeters on the day indicated, (999 = missing data).
SnowDepthSource	See [1], Table 3-5
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
LastSnowfallUncertainty	See [1], Table 3-6
PresentWeather	See [1], Appendix B. Each string contains 10 numeric values. The string can be parsed to determine each of 10 observed weather metrics.

References