Start date errors?

[christopher_wright@sdstate_edu]

I was wondering if anyone has encountered start date errors in the ipcc4 projections, specifically for the sresb1 and sresa2 scenarios. For example, in the output file:

pcmdi.ipcc4.ncar_ccsm3_0.sresb1.run8.daily.tas_A2.SRESB1_8.CCSM.atmd.2080-01-01_cat_2099-12-31.nc

the start date indicated in the time_bnds field is 2079-08-13.

However, when I look at the tas time-series from a grid-cell in northern North Dakota, the first value listed is -1.09 (converted from degrees K to degrees C), obviously a cold summer's day, even for N.D. Subsequent values are below zero, suggesting that the actual start date is closer to the first of the year.

I don't find similar problems for the sresa1b scenario. Any thoughts out there?

 

[strandwg]

I was wondering if anyone has encountered start date errors in the ipcc4 projections, specifically for the sresb1 and sresa2 scenarios. For example, in the output file:

pcmdi.ipcc4.ncar_ccsm3_0.sresb1.run8.daily.tas_A2.SRESB1_8.CCSM.atmd.2080-01-01_cat_2099-12-31.nc

the start date indicated in the time_bnds field is 2079-08-13.

However, when I look at the tas time-series from a grid-cell in northern North Dakota, the first value listed is -1.09 (converted from degrees K to degrees C), obviously a cold summer's day, even for N.D. Subsequent values are below zero, suggesting that the actual start date is closer to the first of the year.

I don't find similar problems for the sresa1b scenario. Any thoughts out there?

Make sure you're taking into account the fixed 365-day year that's used in CCSM. The time value for the first time sample in that file is 759200.5, which gives a date of 1 Jan 2080 (759200.5/365 = 2080 years, 1/2 day). That makes sense with the values for 'tas' that you have observed.

 

[s_namdinh@yahoo_com]

Dear all,

I am a researcher, now I am working for Vietnam Institute Meteorology, Hydrology and Environment. I downloaded the result of CCSM (CCSM run b30.40a – CCSM3 SRES A1B) as a reference to estimate sea level rise in South China Sea . I did it following these steps:

1. I downloaded data for 100 years, each year only 4 month (1, 4, 7, 10) then I have the average value of sea suface high for each year at a cell.

2. I useded ncdump to change data form .nc to .txt

For instance: ncdump b30.040.pop.h.2000-01.nc –v SSH > b30.040.pop.h.2000-01.txt

3. I useded FORTRAN language to get the data at any cell that I want

4. finally, I have the chart from these data

It is very surprised me because of the trend of sea level not as I thinked, instead of rise up, it go down. I have checked all steps a lot of times to find the anwser but it seems to be a difficult problem for me. Can anyone check or explain why it is and how to get the correct data.
Thank you very much