Long-Term Changes in Thickness Temperature of the Lower Atmosphere Calculated from Air Pressure Data in the Central Mountain Region, Japan

Changes in the thickness temperature (TT) of the lower atmosphere from 1961 to 2025 were investigated using air pressure data from eight stations in the Central Mountain region of Japan. The stations were located at elevations ranging from 400 m to 1300 m above sea level. The average linear trend in TT at these stations was 0.25 °C per decade, which was close to the air temperature trend at non-urban stations in the surrounding coastal areas. Despite the presence of some divergence in TT trends across the stations, TT is expected to serve as a complementary index for climate change research, since concerns about spatial representativeness and temporal homogeneity exist in air temperature data.