Signals in the Urban Soils.

The role played by soil in land-atmosphere coupling over forest, crop and rural canopies is well known and widely researched, however the relationship between soils in cities and the urban microclimate is not clearly determined and understood. In fact, even the physical characteristics of the urban soils are not known. An urban soil on a parcel in a metropolitan area has typically been moved, graded, and/or or compacted over time, often as a result of construction and demolition activity at the site. Movement of soil and addition of non-native soils is relatively common in developed areas. Because of the ways soils have been altered, there can be great variation in the characteristics of soils within an urban land parcel. Soil studies in urban areas have found that soil compaction, low organic matter content, and low levels of contamination, usually from air deposition or from historical uses on site, are common attributes of urban soils. However, to what extent the above factors influence the role of the soil, as a key component in the land-atmosphere continuum is unknown and their impact on the urban energy and water cycles at street, neighborhood and city scales is also poorly researched. The primary goal of this study is understand the spatial variability of soil characteristics in New York City (NYC) and to understand their impact on the local microclimate. The outcome from this work will aid in developing urban greening strategies to mitigate the adverse impacts of climate change in cities. Here we will conduct an extensive soil sample analysis at multiple locations in NYC. Our soil sampling will be conducted on locations where the local microclimate is monitored. We have nearly 20 stations located in NYC where we continuously monitor the hydro-meteorological conditions. We will quantify the physical and hydrological characteristics of the soil and map the spatial variability. Our preliminary analysis found sand to be dominant component of the NYC soil composition compared to clay and silt. Sand is made up of quartz crystals which have high porosity compared to clay, which has the capacity to absorb and hold a considerable amount of water. Clay retains water more efficiently and supports plants and micro-organisms.

Keywords: urban soil, green infrastructure, climate