Update exercise_3.ipynb

notebooks/challenge/paleo/exercise_3.ipynb

@@ -232,7 +232,7 @@
     "In isotope-enabled CESM, the relative abundances of $^{16}\\text{O}$ and $^{18}\\text{O}$ are already adjusted to their naturally occurring global abundances (99.757% and 0.205%, respectively), so we do not include $R_{\\text{std}}$ in the calculation of $\\delta^{18}\\text{O}$. Rather, isotope variables in CESM are expressed in delta (δ) notation as: \n",
     "\n",
     "\n",
-    "$$ \\delta^{18}O = (\\frac{\\text{PRECRC\\_H218Or} + \\text{PRECSC\\_H218Os} + \\text{PRECRL\\_H218OR} + \\text{PRECSL\\_H218OS}}{\\text{PRECRC\\_H216Or} + \\text{PRECSC\\_H216Os} + \\text{PRECRL\\_H216OR} + \\text{PRECSL\\_H216OS}} - 1) \\times 1000‰  $$\n",
+    "$$ \\delta^{18}O = (\\frac{\\text{PRECRC_H218Or} + \\text{PRECSC_H218Os} + \\text{PRECRL_H218OR} + \\text{PRECSL_H218OS}}{\\text{PRECRC_H216Or} + \\text{PRECSC_H216Os} + \\text{PRECRL_H216OR} + \\text{PRECSL_H216OS}} - 1) \\times 1000‰  $$\n",
     "\n",
     "\n",
     "- Use ``ncdump /glade/derecho/scratch/$USER/$CASENAME/atm/hist/$CASENAME.cam.h0.0001-01.nc | less`` to check the definition of each isotope variable above \n",