## 3 Results
### Optimization of Microclimate Performance at Street Level
The mean building enclosure degree value of the block showed a significant downward trend and then kept at around 0.6. These results demonstrated that the average building enclosure degree of the block was positively correlated with the street's outdoor comfort ratio; the surrounding blocks with a higher building enclosure degree had a positive contribution with improvement of the middle street's outdoor comfort. Along with the decrease of comfort ratio, the trend of variation of building heights showed a significant step-by-step upward trend. Results illustrated that the smaller variation of building heights was beneficial to improving the microclimate comfort of the street space, while the larger variation of building heights led to poor street microclimate comfort. This finding occurred because the larger variation of building heights indicated an increased building height difference, which guides cold wind into the block's interior by the higher buildings, thus affecting the street's comfort. Nonetheless, previous studies suggested that a higher variation of building heights was also beneficial to increasing the reflection ratio of solar radiation, so more radiation enters the city's interior and improves the microclimate of cold blocks during winter. Regardless, the losses caused by cold air in Shenyang City were clearly more significant than the benefits of radiation. Figure 15: The percentage of building form distribution with optimization of higher than 85% of acceptable UTCI percentage at street level. As for the microclimate indices, the change trend of mean radiation temperature (MRT) was observed (Figure 19), and findings demonstrated that the value of MRT changed irregularly with the decrease of comfort ratio. With the reduction of comfort ratio, the average radiation temperature did not decrease but rather appeared in the poorer generations of optimization, which showed that different from our experience, winter solar radiation in cold-region cities was not a dominant factor in outdoor comfort of the human body. Figure 16: Correlation results of building density, plot ratio, and acceptable UTCI percentage at street level. Figure 17: Correlation results of building enclosure, variation of building heights, and acceptable UTCI percentage at street level. Notably, the change trend of comfort index basically has a linear positive correlation with the change trend of comfort ratio. However, there is not a large fluctuation in the line chart of comfort index, indicating that when average comfort within the test range is high (that is, the overall comfort is high) this does not mean that most of the field area is comfortable. Instead, high comfort indices in some regions may exist with very low comfort indices in other regions, yet this difference cannot be seen in terms of mean value. These results also confirm the rationality of selecting comfort ratio as the optimization index from the lateral perspective, ensuring that the maximum range of urban areas can meet the comfort standard. The change trend of average wind speed and unacceptable wind speed percentage was observed in Figure 20, both showing a decline trend with the decrease of comfort ratio. By comparing the mean wind speed and average solar radiation temperature, we determined that wind is more effective than solar radiation in influencing the comfort of outdoor microclimates during winter in cold-region cities. By comparing the variation trend of average and unacceptable wind speed percentage with the comfort ratio change trend in a descending order, we noticed that although the general trend of average wind speed was similar to that of the comfort percentage, the change trend of unacceptable wind  
Figure 11:0 Correlation results of average UTCI, MRT, and acceptable UTCI percentage at street level. Figure 11:1 Correlation results of SVF and acceptable UTCI percentage at street level. percentage was more consistent with that of comfort percentage.