This is аn imаge frоm yоur reаding 3.2 Structure оf Earth. What does it mean to have a rate of isostatic adjustment of -6 mm/y (like the location at the tip of the arrow)?
Bаckgrоund This midterm uses reаl, publicly аvailable data: mоnthly U.S. tоtal natural gas consumption (all end-use sectors combined — residential, commercial, industrial, and electric power), measured in billion cubic feet (Bcf), not seasonally adjusted. The data are collected by the U.S. Energy Information Administration (EIA, series `NG.N9140US2.M`) and retrieved from FRED, Federal Reserve Bank of St. Louis (series [`NATURALGAS`](https://fred.stlouisfed.org/series/NATURALGAS)). We use January 2005 through December 2019 (180 months): train = 2005–2018, test = 2019 (the last 12 months). Because this is real, weather- and economy-driven data rather than a simulated series, expect messier residuals and more genuinely ambiguous modeling tradeoffs than a textbook example — that is intentional. A note on code: to let you focus on interpreting and reasoning about the models rather than debugging plotting syntax, several code blocks below are already provided (sometimes as a working template, sometimes with a specific value left for you to fill in and justify). Where no code is given, you are expected to write it yourself. Setting up working directory and libraries Make sure to have created a folder called Midterm1 under your local ISyE6402Main folder. The data file should be placed under this folder. The 'Setup Working Directory' code below assumes you have done so. Please note: You are required to submit your final analysis as a PDF file. (Other formats will result in a penalty to the grade.) This exam will give you a practical understanding of working with environmental time series, as well as a chance to demonstrate your ability to apply statistical modeling techniques for forecasting such time series.