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

这是一个项目，目的是开发一种新技术，利用沿沿着恒定密度表面（通常在平流层）飞行的超压气球进行温度剖面测量。 该传感器是光纤温度剖面仪（FTP），由悬挂在气球座舱上的2- 4公里长的光纤组成。 温度是由注入光纤顶部的激光脉冲返回的反向散射沿光纤长度沿着确定的。 光纤温度的变化导致拉曼散射（特别是斯托克斯和反斯托克斯线的波长）的变化，其可以被反转以检索温度，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沿着。 该技术目前用于工业应用（例如，石油和天然气钻探操作中的钻孔温度感测），并且传感器是商业上可获得的。 然而，它需要大量的增强，才能从气球吊舱部署。除了核心仪器，其他几个组件必须开发，以形成一个完整的系统。 其中之一是一个光纤端模块，它被加重以使光纤或多或少垂直悬挂，并包含一个温度计和一个GPS接收器。 GPS接收器确定光纤底端的位置，该位置与来自吊舱中的GPS接收器的位置定位相结合，以估计温度读数的高度。 其他组件包括一个数据和控制系统以及一个光纤部署系统，后者由一个线轴组成，一旦气球达到高度，线轴就会放出光纤。 这里提供的资金将用于开发原型并进行试飞。由于该系统的广泛潜在应用，这项工作具有更广泛的科学影响。 该系统的主要用途是探测热带对流层顶层。 人们对TTL的精细尺度温度结构有相当大的兴趣，特别是因为它涉及的问题包括云顶高度和热带对流层顶冷点高度之间的差异，TTL的最低温度及其在限制水汽输送到平流层中的作用，以及与垂直传播的重力波相关的温度扰动。

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.