Duplicate All Rows

I will be both apologetic and happy, though, if you can suggest a solution that does not require programming. If a programming solution IS required, I'd be grateful if you could give me a note or two on how to run the code if it is necessary. I'm competent with computers and I could program what I need in C++ if I had to, but I haven't used VBA before.

Here's my excel problem:

I have two long sets of data:

One is pressure from a transducer under water (in the river) recorded every 30 minutes. The other is pressure from a transducer above the water recording every hour.

I need to find the pressure due to water for each point (meaning I need to subtract the atmospheric pressure from each point of total pressure). From that, the height of water can be calculated, which will allow me to calculate discharge, or flow, of water at this spot in the river.

Because the atmospheric pressure is only recorded hourly, I need to duplicate each row of the atmospheric data worksheet so I can copy it over and make it the 'subtract' column.

Since I am working with years of data, there are thousands of rows, and the idea of duplicating each row manually is lame.

I tried to figure out a way for my calculation formula to use each row of the 'subtract' column twice (by making the first two subtract the value in E5, the second two use E6, the third pair use E7, and then dragging the auto-fill formula thingy down through the whole data set, but it doesn't work because the first one that gets auto-filled subtracts the value right next to it {..., D9-E7, D10-E7, D11-E11, D12-E11, ...} and so on).

So, like I said, I think i'll probably need to program it. If there was a way get the auto-formula-fill thingy to stop skipping back to the cell directly next to it as soon as it starts over the loop of copying, then that would be great.

Thank you for your help, and I apologize if this has been posted before, but all I could find were like a billion threads on deleting duplicate data.