Averaging my data into quarterly means (nfrequency error message)

August 2, 2022

I’m trying to average my data into quarterly means but when i use the following code i get this error

code

quarterly = aggregate(overturning_ts, nfrequency = 4, mean)

error message

Error in aggregate.ts(overturning_ts, nfrequency = 4, mean) : 
cannot change frequency from 1 to 4

date snippet

overturning_ts
    year month day hour Quarter Days_since_start Overturning_Strength
[1,] 2004     4   2    0       2              1.0             9.689933
[2,] 2004     4   2   12       2              1.5            10.193495
[3,] 2004     4   3    0       2              2.0            10.660849
[4,] 2004     4   3   12       2              2.5            11.077229
[5,] 2004     4   4    0       2              3.0            11.432414
[6,] 2004     4   4   12       2              3.5            11.721769

all data available here, after downloading i just converted it to a time series to get overturned_ts: https://drive.google.com/file/d/1NV3aKsvpPkGatLnuUMbvLpxhcYs_gdM-/view?usp=sharing

outcome i am looking for here;

   Qtr1   Qtr2   Qtr3   Qtr4
1960  160.1  129.7   84.8  120.1
1961  160.1  124.9   84.8  116.9
1962  169.7  140.9   89.7  123.3

>Solution :

Like this?

library(tidyverse)

df %>%  
  group_by(year, Quarter) %>% 
  summarise(avg_overturning = mean(Overturning_Strength, na.rm = TRUE)) %>%  
  pivot_wider(names_from = Quarter, 
              values_from = avg_overturning, names_sort = TRUE)
    
# A tibble: 11 x 5
# Groups:   year [11]
    year   `1`   `2`   `3`   `4`
   <dbl> <dbl> <dbl> <dbl> <dbl>
 1  2004 NA     15.3  23.7  17.7
 2  2005 14.0   18.7  21.7  22.5
 3  2006 17.1   17.7  20.5  20.8
 4  2007 18.9   15.5  17.9  20.0
 5  2008 18.5   15.5  16.1  20.2
 6  2009 16.3   14.9  15.3  12.2
 7  2010  8.89  16.2  19.7  15.1
 8  2011 15.1   16.0  17.8  18.4
 9  2012 15.8   11.9  16.4  16.5
10  2013 11.9   17.1  17.6  18.8
11  2014 15.1   NA    NA    NA