Questions about discrepancies in calculated heating rate

[Aaron-Hsieh-0129]

Hi,

I'm working on calculating the heating rate and have some questions about my results. Based on my understanding, the heating rate in the troposphere should be around -2 K/day, near 0 at the tropopause, and potentially show significant heating in the stratosphere due to ozone absorption. However, my results indicate weaker-than-expected cooling and unexpected heating in the troposphere.

Could this be due to an incorrect method or improper variable selection? Below, I’ve outlined my approach and included relevant details.

Method:

I used the allsky test to generate input data and ran the program with this input (without the cloud-optics option).
I calculated the longwave and shortwave heating rates from the output file using the formula:
Heating rate = $g/C_p \times \text{SecForADay} \times \frac{\Delta F}{\Delta p}$

Results

Code

import numpy as np
import matplotlib.pyplot as plt
import xarray as xr

ds = xr.open_dataset("rte_rrtmgp_output.nc")

p_lay =  np.squeeze(ds['p_lay'].to_numpy())
p_lev =  np.squeeze(ds['p_lev'].to_numpy())
sw_flux_net = np.squeeze(ds['sw_flux_net'].to_numpy())
lw_flux_net = np.squeeze(ds['lw_flux_net'].to_numpy())

sw_heat_rate = 9.8/1004*86400*(sw_flux_net[1:]-sw_flux_net[:-1]) / (p_lev[:-1]-p_lev[1:])
lw_heat_rate = 9.8/1004*86400*(lw_flux_net[1:]-lw_flux_net[:-1]) / (p_lev[:-1]-p_lev[1:])
heat_rate = sw_heat_rate + lw_heat_rate

plt.figure(figsize=(14,10))
plt.plot(heat_rate[:,10], p_lay[:,10], label="Total Heat Rate")
plt.plot(sw_heat_rate[:,10], p_lay[:,10], label="SW Heat Rate")
plt.plot(lw_heat_rate[:,10], p_lay[:,10], label="LW Heat Rate")
plt.xlim(-3,3)
plt.ylim(100000,100)
plt.xlabel("Heating Rate [K/day]")
plt.ylabel("Pressure [Pa]")
plt.legend()
plt.show()

Could you help clarify if my approach or variable choices are causing these discrepancies? Any guidance would be appreciated!

Thanks,
Aaron

[Aaron-Hsieh-0129]

By the way, I thought the results would be similar as this figure from the climatology textbook of Hartmann.