EAGER: Fiber-Optic Temperature Profiler for Long Duration Ballooning - Proof of Concept

这是一个项目，旨在开发一种新的技术，利用超压气球沿着恒定密度表面飞行，通常是在平流层中飞行的温度廓线。该传感器是一种光纤温度剖面仪(FTP)，由悬挂在气球吊篮上的2-4公里长的光纤组成。温度是根据从注入在光纤顶部的激光脉冲返回的后向散射沿光纤长度确定的。光纤温度的变化导致拉曼散射的变化(特别是斯托克斯线和反斯托克斯线的波长)，拉曼散射可以被反转来恢复温度，并且激光脉冲的定时可以用于将温度测量归因于沿着光纤的特定线性位置。这项技术目前被用于工业应用(例如，石油和天然气钻井作业中的钻孔温度传感)，并且传感器已经商业化。然而，在从气球吊篮上展开它之前，它需要有实质性的增强。除了核心仪器之外，还必须开发其他几个部件来形成一个完整的系统。其中之一是光纤末端模块，它被加权以使光纤或多或少垂直悬挂，并包含温度计和GPS接收器。GPS接收器确定光纤底端的位置，该位置与座舱中GPS接收器的位置定位相结合，以估计温度读数的高度。其他组件包括数据和控制系统以及光纤展开系统，后者由一个卷轴组成，一旦气球到达高度，该卷轴就会卷起光纤。这里提供的资金将用于开发原型和进行试飞。由于该系统的潜在应用范围广泛，这项工作具有更广泛的科学影响。该系统主要用于探测热带对流层顶层(TTL)。TTL的细尺度温度结构引起了相当大的兴趣，特别是因为它涉及的问题包括云顶高度与热带对流层冷点顶高度之间的差异、TTL的最低温度及其在限制水蒸气进入平流层方面的作用，以及垂直传播的重力波所引起的温度扰动。

This is a project to develop a new technology for temperature profiling from super-pressure balloons that fly along constant density surfaces, typically in the stratosphere. The sensor is a fiber-optic temperature profiler (FTP), consisting of a 2-4km length of optical fiber suspended from the gondola of a balloon. Temperature is determined along the length of the fiber from the backscatter returned from a laser pulse injected at the top of the fiber. Changes in the temperature of the fiber lead to changes in Raman scattering (particularly the wavelengths of the stokes and anti-stokes lines), which can be inverted to retrieve temperature, and the timing of the laser pulses can be used to ascribe the temperature measurement to a specific linear position along the fiber. This technology is currently used for industrial applications (e.g. borehole temperature sensing in oil and gas drilling operations), and the sensors are commercially available. However, it requires substantial enhancement before it can be deployed from a balloon gondola.In addition to the core instrument, several other components must be developed to form a complete system. One of these is an end-of-fiber module which is weighted to make the fiber hang more or less vertically and contains a thermometer and a GPS receiver. The GPS receiver determines the position of the bottom end of the fiber, which is combined with a position fix from a GPS receiver in the gondola to estimate the altitudes of the temperature readings. Additional components include a data and control system and a fiber deployment system, the latter consisting of a spool that reels out the fiber once the balloon reaches altitude. Funds provided here will be used to develop a prototype and conduct a test flight.The work has scientific broader impacts due to the wide variety of potential applications of the system. The primary intended use of the system is for sounding the Tropical Tropopause Layer (TTL). There is considerable interest in the fine-scale temperature structure of the TTL, particularly as it relates to issues including the difference between cloud-top height and the height of the cold-point tropical tropopause, the minimum temperature of the TTL and its role in limiting the transport of water vapor into the stratosphere, and the temperature perturbations associated with vertically propagating gravity waves.