# Comparison of UAH and RSS Time Series with Common Baseline

In this post I set both UAH 5.4 and RSS 3.3 global temperature anomaly series to a common baseline period (1981-2010)  to compare them. Since both the UAH 5.4 and RSS 3.3 series are satellite based , they exhibit striking similarities.

Common Baseline

In this previous post, I showed how to convert temperature anomaly time series from one baseline period to another period.  I then used this technique in this post to directly compare UAH 5.4 (baseline 1981-2010) and GISS.

In this post, I compare the satellite based UAH 5.4 (baseline 1981-2010) and RSS 3.3 (baseline 1979-1998) series.

The offsets are as follows:

• UAH:  -0.000978

Since the UAH TLT 5.4 series is based on a 1981-2010 baseline, the offset is nearly zero (-0.00098 versus 0.0). The RSS offset changes the baseline from 1979-1998 to 1981-2010.

Users can reproduce my analysis on their own by downloading my CTS.csv file and applying the offsets to the UAH and RSS series.

Comparison of 1981-2010 Baseline Series

Here is a plot of UAH and RSS 12 month moving averages for 1979 to current: Click to Enlarge

Both 12-month moving average series show similar cyclical patterns with  positive trends. The UAH series shows a slightly higher El Nino response than RSS in in several instances, including the 2010 El Nino cycle.

Here is the monthly trend chart for the 2 series: Click to EnlargeThe 2 satellite  series track each other quite well.

We can examine the delta (delta = UAH – RSS) between the two series to see the actual differences between the series each month. Click to Enlarge.In the 1979 – 2011 period, UAH has been greater than RSS 50.7%.

Here is a scatter plot of the 2 series: Click to Enlarge.

This scatterplot shows that RSS 3.3 and UAH 5.4 are in good agreement when the baselines are set to a common period.

Setting the UAH and RSS series to the same 1981 – 2010 baseline shows how close the 2 satellite series are:

• Both series exhibit strong cyclical patterns, attributable in part to El Nino – La Nina cycles
• Both show upward trend
• Timing of cycles is comparable
• UAH is greater than RSS 50.7 % of months, very close to expected 50% of time

### 4 responses to “Comparison of UAH and RSS Time Series with Common Baseline”

1. This is really an evocative article I gone through. Thanks for this info sharing.

2. If I understand properly, you are taking the mean of both time series from 1981-2010 and subtracting those means from their respective series. This is the correct procedure for annual data, but not if the data is monthly. You have to calculate the January mean, February mean, etc. Then subtract those means from their respective months.

3. Robert

Hey kelly,

Great post as usual. Was trying to do something and was wondering if you had any ideas on the best way to do it.

Have a series of climate reconstructions each starting at different times covering the period 0 to 2000 AD

Want to do a simple subtraction on each series (for example year 4 temp minus year 2 temp, year 5 temp minus year 3 temp etc…) and have an output which is essentially a .csv with all the adjusted values if that makes sense?