WMS Climate City Bremen

Web Map Service (MWS) Climate of the Municipality of Bremen.

Bioclimatic situation (climate function map):
The climate function map shows the functions and processes of nocturnal air exchange for the urban area of Bremen (flow field, cold air ducts). For residential and commercial areas, it represents the nightly overheating, based on the ground-level air temperature in an autochthonous summer night at 04:00 in the morning.

Bioclimatic situation of settlement areas (with cold air exposure area)

• Settlement areas in the exposure area of the cold air flow:
Settlement areas that are permeated by nocturnal cold air.
The cold air exposure area characterizes the ground-level outflow of cold air from the green areas into the
adjoining buildings during an autochthonous summer night. As a cold air exposure area, settlement and
commercial areas within the city area, which are characterized by an above-average
cold air volume flow or are characterized by a wind speed of at least 0.2 m s-1.

• Bioclimatic situation of settlement areas:
Classification of the bioclimatic situation into four classes (very favorable, favorable, less favorable, unfavorable) in relation to the local mean based on the z-transformed PMV value (predicted mean vote).
Settlement areas can be divided into sufficiently ventilated areas and thus mostly climatically favorable settlement structures as well as climatic stress areas. The nighttime overheating is due to the temperature difference to the green areas of the city. The heat island effect results as a deviation from this reference value and is therefore a more suitable parameter for recording the urban climate effect than absolute temperature values.

Bioclimatic importance of green and open spaces (cold air generation/production)

• Areas with very high cold air generation/production:
Green areas with very high cold air production are areas that have more than above-average cold air production in relation to the mean value in the examination room. They are marked by dot symbols. Selection criterion is a z-transformed cold air production rate greater than 1.
Cold air production areas characterize green areas with a significantly above-average cold air production rate and feed the cold air exchange areas or extend beyond them.

• Bioclimatic importance of green spaces and open spaces:
Classification of the urban climatic importance of green areas into four classes (small, medium, high, very high).
In the climate function map, green areas and open spaces are characterized with regard to their cold air supply capacity. Areas producing cold air (cold-air production areas) include unsealed open spaces (e.g. meadows, pastures and arable land) as well as green areas (e.g. park areas, allotments and cemetery areas) and forests characterised by loose vegetation. For the characterization of this compensation power, the cold air volume flow from adjacent areas is drawn in.

• Settlement areas with a climate-relevant function:
In individual cases, cold air can also be conveyed via settlement areas with low building density, low building heights and/or a high proportion of greenery. These settlement areas with very high cold air volume flows have a guideway similar function within the settlement area and are designated with a horizontal hatching.

• Air exchange:
Classification or evaluation of the cold air supply capacity of green areas in relation to the regional average (z-transformed cold air volume flow).
Cold air exchange areas connect cold air development areas (compensation rooms) and load areas (effect rooms) via (local or higher-level) cold air ducts or fulfill an important ventilation function and are therefore an elementary part of the air exchange.

不来梅市Web地图服务（Web Map Service, MWS）气候数据集。

生物气候状况（气候功能图）：
气候功能图展示了不来梅城区夜间空气交换的功能与过程（流场、冷空气通道）。该图基于本地夏季凌晨04:00的近地面气温，表征了居住区与商业区的夜间过热现象。

聚居区生物气候状况（含冷空气暴露区域）
• 处于冷空气流暴露区域的聚居区：指被夜间冷空气渗透的聚居区域。冷空气暴露区域表征了本地夏季夜间绿地近地面冷空气向外输送至周边建筑的过程。作为冷空气暴露区域，城区内的聚居与商业区需满足以下任一特征：冷空气体积流量高于平均水平，或风速不低于0.2 m·s⁻¹。
• 聚居区生物气候状况：基于经z变换的预测平均投票值（predicted mean vote, PMV）结合局地平均值，将生物气候状况划分为四个等级（极优、优良、一般、较差）。聚居区可分为通风充足区域（此类区域大多气候条件适宜）与气候压力区域。夜间过热源于与城市绿地的温差，热岛效应表现为相对于参考值的偏差，因此相较于绝对气温值，热岛效应是表征城市气候效应更合适的参数。

绿地与开放空间的生物气候重要性（冷空气生成量）
• 冷空气生成量极高的区域：指研究范围内冷空气生成量高于平均水平的绿地。此类区域以点状符号标注，筛选标准为经z变换的冷空气生成率大于1。冷空气生成区域指冷空气生成率显著高于平均水平的绿地，它们可为冷空气交换区域提供补给或延伸至该区域之外。
• 绿地与开放空间的生物气候重要性：将绿地的城市气候重要性划分为四个等级（低、中、高、极高）。在气候功能图中，绿地与开放空间依据其冷空气供给能力进行表征。冷空气生成区域（冷空气生产区）包括未铺装开放空间（如草地、牧场与耕地）、绿地（如公园地块、自留地与墓园）以及植被稀疏的林地。为表征该补偿能力，需引入相邻区域的冷空气体积流量。
• 具备气候相关功能的聚居区：在特定情况下，低密度、低层高或绿地占比高的聚居区也可输送冷空气。此类聚居区的冷空气体积流量极高，在聚居区内发挥类似通道的作用，以水平斜线阴影标注。
• 空气交换：基于区域平均值（经z变换的冷空气体积流量）对绿地的冷空气供给能力进行分类与评估。冷空气交换区域通过（局地或更高层级的）冷空气通道连接冷空气生成区域（补偿区）与负荷区域（效应区），或承担重要的通风功能，因此是空气交换过程的核心组成部分。