Can anything be done to help calm down a noisy baseline?

Assuming the noise along your baseline is not due to anything electronic within your detector, there are two things that can be done to help minimize this problem.

First, you can adequately degas your solvents. Following the flow path, the solvent stream moves quickly from a high-pressure environment within the column to a low-pressure environment on the effluent side of the column. Often, if solvents are not properly degassed, the gases being forced to remain dissolved in solution due to the high pressure inside and upstream from the column quickly outgas when the pressure changes. This outgassing is visible in the form of bubbles in the solvent stream line. These bubbles can pass into your flow cell, and once there they can cause excessive noise. Adequate degassing can help eliminate the problem of outgassing and thus help eliminate the chance of bubbles forming in the flow cell.

The second thing you can do to help eliminate this problem is to use a back pressure regulator on the effluent side of your flow cell, because one of the primary factors causing bubbles to form in the solvent stream is the drastic drop in pressure the solvent experiences. Using a back pressure regulator forces additional pressure along the flow path, thus helping to ensure that any gas dissolved in the mobile phase stays dissolved until it has passed through the detector flow cell.