In this post, I use a quadratic regression model to forecast the September, 2011 Arctic Sea Ice Extent. The model was developed with 1980 – 2010 data. Links to the R script, source data and how-to article on polynomial regression are provided.
Arctic Sea Ice Extent Forecast for September, 2011
First, here is my forecast: (Click image to enlarge)
Based on the 1980 – 2010 downward Arctic Sea Ice trend, my forecast is that September, 2011 SIE will decline 0.36 below 2010 levels, to 4.54 million km^2, with a confidence band of +- 0.59.
How Did I Develop My Forecast?
I have written a number of posts on Arctic Sea Ice Extent (here, here, here). In this post, I used the NSDIC‘s monthly data file (link) to construct a quadratic regression model of September sea ice extent for the 1980 – 2010 period. I then used this model to predict the September, 2011 Arctic Sea Ice Extent.
I have 2 main learning curve sources for this model:
- Tamino‘s post on Arctic Sea Ice decline provided the basic idea of using a quadratic model to fit Arctic SIE decline.
- John Quick’s tutorial on polynomial regression provided the how-to instructions I needed to implement Tamino’s approach in R.
RClimate Script and Links
Here is the link to my RClimate script.
I am pleased to announce my CTS.csv file which includes 18 climate monthly time series in one easy to access csv file. This is part of my goal of having a user friendly way for do-it-yourself citizen climate scientists to get up-to-date agency climate time series in a painless way.
Update 1: Reader Scott asked if I could provide meta data for the columns in my CTS.csv. This page lists the source agency and data links for the climate data series.
Here’s a snap shot of the first 6 rows of my CTS.csv file. The data extends from 1880 until the most recent month. Click image to enlarge
My hope is to make the CTS.csv the go-to file for citizen climate scientists who may want to:
- Check temperature anomalies trends by series (GISS, HAD, NOAA, RSS, UAH)
- Assess climate oscillations(AMO, AO, MEI, Nino34, PDO) trends
- Evaluate CO2 versus temperature anomaly relationships
- Evaluate relationship between Sunspot numbers and anomaly temperature anomaly trends
- Compare atmospheric transmission, SATO index and volcanic activity
- Assess impact of volcanoes on temperature anomaly trends
- Compare MEI versus Nino ENSO 34 indicators
- Assess lower stratospheric trends using RSS’s TLS series
By having these climate time series in a single csv file, R and Excel users can work with up to date data in a convenient form. The file will be automatically updated monthly as the climate agencies release their latest data.
How can CTS.csv Help Do-It-Yourself Citizen Climate Scientists?
Interested climate observers who want to compare global SSTA versus Nino34 trends, for example, have to follow a multiphase process:
- Find data file – even with Google this can take time
- Download files
- Merge 2 or more files to get data into a usable format – source files all have different formats
- Perform analysis
Steps 1-3 can be very time consuming, so many users don’t bother checking out their ideas. Rather, they may rely on climate blog comments. With CTS.csv and some R or Excel analysis, they can find the facts themselves rather than just having opinions. They can submit their analysis and charts to blog posts, hopefully increasing the rigor of blog discussions.
Climate bloggers can request that their readers submit charts to back up their climate trend claims.
Data & RClimate Scripts Are All Open Book
All of the RClimate script that I use to produce the CTS.csv is available on-line at this link. Source data links are included in the function for each series.
This post shows how to use RClimate.txt to retrieve a climate time series and write a csv file in 5 lines of R script.
One of my readers, Robert, wants to be able to download climate time series data and write it to a csv file. The R script below shows how to download the MEI data series and write a csv file. For this example I will use the RClimate function (func_MEI) to retrieve the data. I then simply specify the path and file name link for the output file (note quotes around the output file name and then write a csv file.
m <- func_MEI()
output_link <- "C://R_Home/mei.csv"
write.csv(m, output_link, quote=FALSE, row.names = F)
In previous posts I have shown plots of global temperature anomaly, volcano and Nino34 trends (here , here). In this post , I want to further explore the role of volcanic eruptions and Nino34 phases (El Nino, La Nina) on temperature anomalies.
This post shows a 5-panel chart of monthly climate trend data: 1) time line of major volcanoes and Volcanic Explosivity Index (VEI), 2) Mauna Loa Observatory (MLO) Atmospheric Transmission (AT) measurements, 3) Stratospheric Aerosol Optical Thickness (SATO) Index, 4) , Nino 34 as an indicator of ENSO and 5) GISS land-ocean temperature anomaly.
The RClimate script and Climate Time Series data file (CTS.csv) links are provided.
First, here is the 5-panel chart that I have made showing the monthly volcano time line with Volcano Explosivity Index (VEI) , Atmospheric Transmission at Mauna Loa Observatory, SATO Index as well as the Nino34 SSTA and GISS LOTA. (Click Image to Enlarge)
While there are many online climate data resources, the source data files are in numerous data formats, presenting a challenge to climate citizen scientists who want to retrieve and analyze several climate indicators at the same time.
I have been working to develop a consolidated open access data file and RClimate scripts that users can use to retrieve climate data, conduct their own analysis and generate their own climate charts. My goal is to make it easier for climate citizen scientists to get their hands on the data in a simple, usable format (CSV). This post updates the status of my RClimate efforts.
As a former Excel chart user, I want to help current Excel users make the transition to more advanced charting R with as little difficulty as possible. This post introduces my LearnR Toolkit to help Excel users move up to R in a systematic, step by step fashion.
As an Excel chart user, I wanted to produce panel charts like this:
The 5 global land-ocean temperature anomaly (LOTA) series use different baseline periods, making direct comparisons between the series more difficult than it would be if each series had the same baseline period.
This post shows how to convert the 5 major LOTA series to a common baseline. Links to on-line source data file and RClimate script are provided. Here is long term LOTA trends using a 133 month moving average and 1979-2008 baseline.
Click to enlarge