Aims

UK-DNDC model was modified to (1) enhance the estimates of soil temperature and N₂O emissions in Denitrification Decomposition (DNDC) model by considering snow melt and frozen and unfrozen conditions along with the impacts of water flux density, thermal diffusivity, crop-canopy, snowmelt routine and snow-depth on N₂O emission and (2) validate the modified DNDC model against measured data from five experimental cropping sites located in the west Canada.

Methods

Heat transfer processes and snowmelt routine of the DNDC have been modified to account for soil heat and water fluxes driven by snowmelt routine and their effects on denitrification and N₂O emissions. The modified DNDC model was tested against the data from five sites, Canada. Then, the model was used to predict the spatial and temporal change of snowpack depth, soil temperature and N₂O emissions.

Results

The validation results show that the modified model predicted daily soil mean temperature and daily N₂O fluxes accurately in all seasons with very high average Pearson’s correlation coefficients at the three sites (R_avg = 0.91 and 0.85 for soil temperature and N₂O emissions, respectively).

Conclusions

The modelled N₂O emissions were sensitive to snowmelt and freeze-thaw cycle in the cold climate region while the modelled soil temperature was sensitive to water flux. This provides a tool for N₂O estimate in Canada and should also be appropriate for utilize in the similar cold climate regions.

中文翻译：

---

用于评估加拿大农业土壤温度和一氧化二氮排放的改进 UK-DNDC 模型

宗旨

UK-DNDC模型进行了改进：（1）提高土壤温度和N的估计_2个通过考虑雪融化和冻结解冻条件与水通量密度，热扩散率，作物的影响沿O排放在反硝化分解（DNDC）模型- 冠层、融雪常规和积雪深度对 N ₂ O 排放的影响；(2) 根据来自加拿大西部五个试验种植点的测量数据验证修改后的 DNDC 模型。

方法

DNDC 的传热过程和融雪程序已经过修改，以考虑由融雪程序驱动的土壤热量和水通量及其对反硝化和 N ₂ O 排放的影响。修改后的 DNDC 模型针对来自加拿大的五个站点的数据进行了测试。然后，该模型用于预测积雪深度、土壤温度和N ₂ O 排放的时空变化。

结果

验证结果表明，修正模型准确预测了所有季节的日土壤平均温度和日 N ₂ O 通量，三个地点的平均 Pearson 相关系数非常高（土壤温度和 N ₂ O 排放的R _avg  = 0.91和0.85，分别）。

结论

模拟的 N ₂ O 排放对寒冷气候区的融雪和冻融循环敏感，而模拟的土壤温度对水通量敏感。这为加拿大的N ₂ O 估计提供了一个工具，也应该适用于类似的寒冷气候地区。