# Numerical Fit Modeling for Temperature Mitigation in
## 1 Introduction  
Some of the problems of global climate change (GCC) can be reduced by solar radiation management (SRM), which alters the radiative properties of the atmosphere. An example is releasing materials such as the mineral calcite or sulfur into the stratosphere [1]. SRM would have effects globally, so ethically it would require approval worldwide [2]. People need to be involved in decision making that affects them. One of the primary ethical concerns is whether the availability of climate engineering would reduce the implementation of greenhouse reductions because it can be seen as an alternative. This is a difficult issue that should be discussed in its own paper. Local initiatives mostly focus on reducing local emissions of greenhouse gases [3] or through changes in the urban infrastructure to mitigate the buildup of heat locally [4]. In arid cities, it is recommended to reduce the heat island effect by increasing vegetation and water, reducing anthropogenic heat generation, and using cooling materials [5]. A difficulty with this approach is that it needs to be implemented household by household. Alternatively, weather modification at a regional scale could be performed for mitigation of heat waves. Plumes of particulates could be made over cities at low altitudes to cool them. Precedents for weather modification are altering cloud properties such as for increasingprecipitation or reducing hail or fog. The paper will show the development of a modeling tool to predict temperature changes resulting from calcite aerosols at the local level. Synoptic, or large-scale, air movements are not considered here. An advantage of focusing on local mitigation is that people have local control over decisions that affect them. Previous work has developed tools for the modeling of heat mitigation using calcite aerosols in humid regions [6]. The goal of this paper is to develop a tool for arid regions. The previous work used the community atmospheric model (CAM), which ran on a supercomputer. The analyses were limited to cases that had been previously installed on the computer and validated by other researchers. Those cases only included models of humid regions. The hypothesis of this work is that a numerical fit model can accurately represent the results so that it can be easily applied to any city in humid or arid climates. The single-column model for CAM is limited to 15 cases that have been developed by the application programmers. These cases focus on locations that have interesting meteorology, such as humid regions. However, weather in arid regions has been investigated less since it is less complex. Therefore, there are no cases available that can be applied there. To develop the modeling tools, it is necessary to first describe the operational plan. However, it is not within the scope of this paper to show complete engineering plans and cost analyses. Those will appear in follow-up papers. Calcite will be used to mitigate high temperatures because it has exceptional radiant properties [7; 8]. Calcite is a common mineral found in limestone. Reflection of radiation depends on the wavelength. Calcite causes near-infrared radiation to reflect, but it does so less effectively in the longwave band [9]. That means that it will have lesser effects on ground radiation. The plume of calcite would be generated during daytime hours only so that it would reduce solar radiation. The material would need to be continually regenerated at varying rates depending on the wind speed. A maximum operating speed would be set based on economics. If larger particles are used, they would be controlled by gravity and would go through rapid settling. If smaller particles are used, they would more commonly go through wet removal further downwind. The particles may be released into the atmosphere from tall towers or from aircraft. The common public may refer to this as creating a dust cloud, but the term cloud is more appropriately used for water, ice, or sulfate masses. Likewise, the term dust often implies naturally produced particles.