I-Corps: A low cost GPS snow sensor

雪是区域和全球气候系统的重要组成部分，也是水文循环中的关键储存组成部分。特别有趣的是雪水当量(SWE)，它同时考虑了深度和密度。然而，目前可用于测量SWE的方法和传感器，甚至仅限于积雪深度，要么局限于单个点，要么昂贵(例如，基于飞机的方法)。远程确定积雪深度的一种新兴选择是利用现有的GPS基站网络，CU教授克里斯汀·M·拉森(PI)、埃里克·E·斯莫尔(共同PI)、马克·W·威廉姆斯和丹尼斯·M·阿科斯目前正在NSF的资助下进行研究。多路径，即信号在地面和其他附近表面的反射，在这里被用来估计相对较大区域的积雪深度。然而，这种方法有两个缺点。包括接收器和天线的测量级基站价格昂贵，约为2万美元，而且由于测地型天线旨在缓解低海拔信号，因此与定制解决方案相比，由此产生的估计质量会受到影响。为了克服这一点，该项目建议开发和营销一种基于大众市场GPS接收器和定制天线的积雪传感器，这种传感器可能会以低成本、合理数量生产。该传感器还具有估计土壤水分含量和植被生长的潜力。目前，可用的积雪深度信息在时间和/或空间上是有限的，关于潜在可用于径流的雪水当量的当前状态的知识也同样有限。因此，广泛部署的负担得起和准确的广域积雪传感器网络将增加对水文循环的知识和理解，并有可能改善气候和天气模型。此外，它还可能被证明对水管理设施很有价值，因为在预测干旱时，积雪水平是一个重要的信息来源。此外，农民和旅游业也可能受益于这种传感器可以提供的信息。土壤水分和植被生长也可以用雪传感器测量，但还需要更多的研究工作来评估全部能力。样机和生产单位将用原始数据“呼叫总部”，而不是直接提供测量结果。然后，用户可以在线访问已处理的预估。这有几个好处；它提供了一种方便的数据访问方法，随着更多的数据和洞察力的出现，它允许改进算法，而且还可以由用户自行决定将数据提供给科学界。

Snow is an important component of both regional and global climate systems, as well as a critical storage component in the hydrologic cycle. Of particular interest is the snow water equivalent (SWE) which considers both depth and density. However, the methods and sensors currently available to measure SWE, or even just snow depth, are either restricted to a single point or expensive (e.g., aircraft based methods.) An emerging option for remotely determining snow depth is the utilization of existing networks of GPS base stations, as is currently being investigated by CU professors Kristine M. Larson (PI), Eric E. Small (co-PI), Mark W. Williams and Dennis M. Akos under NSF grants. Multipath, the reflection of signals off the ground and other nearby surfaces, is here used to estimate the snow depth over a comparably large area. However, this method has two drawbacks. A survey-grade basestation including receivers and antennas is expensive, around $20k, and since geodesy-type antennas are designed to mitigate low elevation signals the resulting quality of the estimates suffers compared to what could be offered by a custom solution. To overcome this, this project proposes the development and marketing of a snow sensor based on a mass-market GPS receiver coupled with a custom antenna, that potentially can be produced at low cost in reasonable quantities. The sensor also has the potential to be used to estimate soil moisture content and vegetation growth.At present, available snow depth information is temporally and/or spatially limited, the knowledge about the current state of the snow water equivalent potentially available for runoff is similarly limited. Thus, a widely-deployed network of affordable and accurate wide area snow sensors will increase the knowledge and understanding of the hydrologic cycle and potentially improve both climate and weather models. Furthermore, it may also prove valuable for water management facilities where snow levels are an important source of information when predicting droughts. Also, farmers and the tourism industry are also likely to benefit from the information this sensor can provide. It is possible that soil moisture and vegetation growth can also be measured with the snow sensor, however additional research effort will be required to assess the full capabilities. The prototypes and production units will "call home" with the raw data rather than provide measurements directly. The users can then access processed estimates online. This has several benefits; it offers a convenient method of accessing data, it allows for refinement of the algorithms as more data and insight becomes available and it is also possible, at the users' discretion, to make the data available to the scientific community.