  Advancements in numerical weather prediction models have accelerated,
fostering a more comprehensive understanding of physical phenomena pertaining
to the dynamics of weather and related computing resources. Despite these
advancements, these models contain inherent biases due to parameterization and
linearization of the differential equations that reduce forecasting accuracy.
In this work, we investigate the use of a computationally efficient deep
learning method, the Convolutional Neural Network (CNN), as a post-processing
technique that improves mesoscale Weather and Research Forecasting (WRF) one
day forecast (with a one-hour temporal resolution) outputs. Using the CNN
architecture, we bias-correct several meteorological parameters calculated by
the WRF model for all of 2018. We train the CNN model with a four-year history
(2014-2017) to investigate the patterns in WRF biases and then reduce these
biases in forecasts for surface wind speed and direction, precipitation,
relative humidity, surface pressure, dewpoint temperature, and surface
temperature. The WRF data, with a spatial resolution of 27 km, covers South
Korea. We obtain ground observations from the Korean Meteorological
Administration station network for 93 weather station locations. The results
indicate a noticeable improvement in WRF forecasts in all station locations.
The average of annual index of agreement for surface wind, precipitation,
surface pressure, temperature, dewpoint temperature and relative humidity of
all stations are 0.85 (WRF:0.67), 0.62 (WRF:0.56), 0.91 (WRF:0.69), 0.99
(WRF:0.98), 0.98 (WRF:0.98), and 0.92 (WRF:0.87), respectively. While this
study focuses on South Korea, the proposed approach can be applied for any
measured weather parameters at any location.
