fluh_timeseries YEAR isn't like flanduse_timeseries YEAR

[samsrabin]

First of all, let me say that I don't think this is an issue. The variable data seems to be the same! However, the differing time axis attributes—and/or maybe something else causing YEAR to not be parsed by ncdump—did confuse me for a while, so it might be worth considering making these consistent.

In the CLM flanduse_timeseries file, the YEAR variable is the actual year.

f=/glade/campaign/cesm/cesmdata/cseg/inputdata/lnd/clm2/surfdata_esmf/ctsm5.2.0/landuse.timeseries_0.9x1.25_SSP2-4.5_1850-2100_78pfts_c240216.nc
ncdump -h $f | grep time | grep -v time,; ncdump -v YEAR $f | tail

netcdf landuse.timeseries_0.9x1.25_SSP2-4.5_1850-2100_78pfts_c240216 {
	time = UNLIMITED ; // (251 currently)
		PCT_CROP_MAX:long_name = "maximum total percent crop landunit during time period" ;
		PCT_NAT_PFT_MAX:long_name = "maximum percent plant functional type during time period (% of landunit)" ;
		PCT_CFT_MAX:long_name = "maximum percent crop functional type during time period (% of landunit)" ;
	int YEAR(time) ;
	int time(time) ;
		time:long_name = "year" ;
		time:units = "unitless" ;
    1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
    2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
    2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026, 2027, 2028,
    2029, 2030, 2031, 2032, 2033, 2034, 2035, 2036, 2037, 2038, 2039, 2040,
    2041, 2042, 2043, 2044, 2045, 2046, 2047, 2048, 2049, 2050, 2051, 2052,
    2053, 2054, 2055, 2056, 2057, 2058, 2059, 2060, 2061, 2062, 2063, 2064,
    2065, 2066, 2067, 2068, 2069, 2070, 2071, 2072, 2073, 2074, 2075, 2076,
    2077, 2078, 2079, 2080, 2081, 2082, 2083, 2084, 2085, 2086, 2087, 2088,
    2089, 2090, 2091, 2092, 2093, 2094, 2095, 2096, 2097, 2098, 2099, 2100 ;
}

However, in the FATES fluh_timeseries file it's more complicated. This can't be inspected using ncdump for some reason:

f=/glade/campaign/cesm/cesmdata/cseg/inputdata/lnd/clm2/surfdata_map/fates-sci.1.68.3_api.31.0.0_tools.1.0.1/LUH2_states_transitions_management.timeseries_4x5_hist_simyr1850-2015_c231101.nc
ncdump -h $f | grep time | grep -v time,; ncdump -v YEAR $f | tail

netcdf LUH2_states_transitions_management.timeseries_4x5_hist_simyr1850-2015_c231101 {
	time = 166 ;
	double time(time) ;
		time:_FillValue = nan ;
		time:units = "years since 850-01-01 0:0:0" ;
		time:calendar = "noleap" ;
		time:long_name = "time" ;
		time:standard_name = "time" ;
		time:axis = "T" ;
	double YEAR(time) ;
data:

 YEAR = _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
    _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
    _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
    _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
    _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
    _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
    _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _ ;
}

However, xarray can see it if you tell it not to decode times:

import xarray as xr
f = "/glade/campaign/cesm/cesmdata/cseg/inputdata/lnd/clm2/surfdata_map/fates-sci.1.68.3_api.31.0.0_tools.1.0.1/LUH2_states_transitions_management.timeseries_4x5_hist_simyr1850-2015_c231101.nc"
ds = xr.open_dataset(f, decode_times=False)
ds["YEAR"].values

array([1850., 1851., 1852., 1853., 1854., 1855., 1856., 1857., 1858.,
       1859., 1860., 1861., 1862., 1863., 1864., 1865., 1866., 1867.,
       1868., 1869., 1870., 1871., 1872., 1873., 1874., 1875., 1876.,
       1877., 1878., 1879., 1880., 1881., 1882., 1883., 1884., 1885.,
       1886., 1887., 1888., 1889., 1890., 1891., 1892., 1893., 1894.,
       1895., 1896., 1897., 1898., 1899., 1900., 1901., 1902., 1903.,
       1904., 1905., 1906., 1907., 1908., 1909., 1910., 1911., 1912.,
       1913., 1914., 1915., 1916., 1917., 1918., 1919., 1920., 1921.,
       1922., 1923., 1924., 1925., 1926., 1927., 1928., 1929., 1930.,
       1931., 1932., 1933., 1934., 1935., 1936., 1937., 1938., 1939.,
       1940., 1941., 1942., 1943., 1944., 1945., 1946., 1947., 1948.,
       1949., 1950., 1951., 1952., 1953., 1954., 1955., 1956., 1957.,
       1958., 1959., 1960., 1961., 1962., 1963., 1964., 1965., 1966.,
       1967., 1968., 1969., 1970., 1971., 1972., 1973., 1974., 1975.,
       1976., 1977., 1978., 1979., 1980., 1981., 1982., 1983., 1984.,
       1985., 1986., 1987., 1988., 1989., 1990., 1991., 1992., 1993.,
       1994., 1995., 1996., 1997., 1998., 1999., 2000., 2001., 2002.,
       2003., 2004., 2005., 2006., 2007., 2008., 2009., 2010., 2011.,
       2012., 2013., 2014., 2015.])