pydaymet.core
Contents
pydaymet.core
#
Core class for the Daymet functions.
Module Contents#
- class pydaymet.core.Daymet(variables=None, pet=None, snow=False, time_scale='daily', region='na')#
Base class for Daymet requests.
- Parameters
variables (
str
orlist
ortuple
, optional) – List of variables to be downloaded. The acceptable variables are:tmin
,tmax
,prcp
,srad
,vp
,swe
,dayl
Descriptions can be found here. Defaults to None i.e., all the variables are downloaded.pet (
str
, optional) – Method for computing PET. Supported methods arepenman_monteith
,priestley_taylor
,hargreaves_samani
, and None (don’t compute PET). Thepenman_monteith
method is based on Allen et al.1 assuming that soil heat flux density is zero. Thepriestley_taylor
method is based on Priestley and TAYLOR2 assuming that soil heat flux density is zero. Thehargreaves_samani
method is based on Hargreaves and Samani3. Defaults toNone
.snow (
bool
, optional) – Compute snowfall from precipitation and minimum temperature. Defaults toFalse
.time_scale (
str
, optional) – Data time scale which can be daily, monthly (monthly summaries), or annual (annual summaries). Defaults to daily.region (
str
, optional) – Region in the US, defaults to na. Acceptable values are:na: Continental North America
hi: Hawaii
pr: Puerto Rico
References
- 1
Richard G Allen, Luis S Pereira, Dirk Raes, Martin Smith, and others. Crop evapotranspiration-guidelines for computing crop water requirements-fao irrigation and drainage paper 56. Fao, Rome, 300(9):D05109, 1998.
- 2
Charles Henry Brian Priestley and Robert Joseph TAYLOR. On the assessment of surface heat flux and evaporation using large-scale parameters. Monthly weather review, 100(2):81–92, 1972.
- 3
George H. Hargreaves and Zohrab A. Samani. Estimating potential evapotranspiration. Journal of the Irrigation and Drainage Division, 108(3):225–230, sep 1982. URL: https://doi.org/10.1061%2Fjrcea4.0001390, doi:10.1061/jrcea4.0001390.
- static check_dates(dates)#
Check if input dates are in correct format and valid.
- dates_todict(dates)#
Set dates by start and end dates as a tuple, (start, end).
- dates_tolist(dates)#
Correct dates for Daymet accounting for leap years.
Daymet doesn’t account for leap years and removes Dec 31 when it’s leap year.
- separate_snow(clm, t_rain=T_RAIN, t_snow=T_SNOW)#
Separate snow based on Martinez and Gupta4.
- Parameters
clm (
pandas.DataFrame
orxarray.Dataset
) – Climate data that should includeprcp
andtmin
.t_rain (
float
, optional) – Threshold for temperature for considering rain, defaults to 2.5 degrees C.t_snow (
float
, optional) – Threshold for temperature for considering snow, defaults to 0.6 degrees C.
- Returns
pandas.DataFrame
orxarray.Dataset
– Input data withsnow (mm/day)
column if input is apandas.DataFrame
, orsnow
variable if input is anxarray.Dataset
.
References
- 4
Guillermo F. Martinez and Hoshin V. Gupta. Toward improved identification of hydrological models: a diagnostic evaluation of the “abcd” monthly water balance model for the conterminous united states. Water Resources Research, 2010. URL: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2009WR008294, arXiv:https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2009WR008294, doi:https://doi.org/10.1029/2009WR008294.
- years_todict(years)#
Set date by list of year(s).